Manual de Taller KAWASAKI KX125-250 (KX125M7F) MANUAL TALLER 2007

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This quick reference guide will assist

you in locating a desired topic or pro-

cedure.

•Bend the pages back to match the

black tab of the desired chapter num-

ber with the black tab on the edge at

each table of contents page.

•Refer to the sectional table of contents

for the exact pages to locate the spe-

cific topic required.

Quick Reference Guide

General Information 1 j

Periodic Maintenance 2 j

Fuel System 3 j

Cooling System 4 j

Engine Top End 5 j

Engine Right Side 6 j

Engine Removal/Installation 7 j

Engine Bottom End/Transmission 8 j

Wheels/Tires 9 j

Final Drive 10 j

Brakes 11 j

Suspension 12 j

Steering 13 j

Electrical System 14 j

Appendix 15 j

KX125

KX250

Motorcycle

Service Manual

transmitted in any form or by any means, electronic mechanical photocopying, recording or otherwise,

without the prior written permission of Quality Divis ion/Consumer Products & Machinery Company/Kawasaki

Heavy Industries, Ltd., Japan.

No liability can be accepted for any inaccuracies or omissions in this publication, although every possible

care has been taken to make it as complete and accurate as possible.

The right is reserved to make changes at any time without prior notice and without incurring an obligation

to make such changes to products manufactured previously. See your Motorcycle dealer for the latest

information on product improvements incorporated after this publication.

All information contained in this publication is based on the latest product information available at the time

of publication. Illustrations and photographs in this publication are intended for reference use only and may

not depict actual model component parts.

LIST OF ABBREVIATIONS

A ampere(s) lb pound(s)

ABDC after bottom dead center m meter(s)

AC alternating current min minute(s)

ATDC after top dead center

newton(s)

BBDC before bottom dead center Pa pascal(s)

BDC bottom dead center PS horsepower

BTDC before top dead center psi pound(s) per square inch

°C degree(s) Celsius r revolution

DC direct current rpm revolution(s) perminute

farad(s)

TDC

top dead center

°F degree(s) Fahrenheit TIR total indicator reading

ft foot, feet Vvolt(s)

ggram(s) W watt(s)

h hour(s) Ω ohm(s)

L liter(s)

Read OWNER’S MANUAL before operating

Foreword

This manual is designed primarily for use by

trained mechanics in a properly equipped shop.

However, it contains enough detail and basic in-

formation to make it useful to the owner who de-

sires to perform his own basic maintenance and

repair work. A basic knowledge of mechanics,

the proper use of tools, and workshop proce-

dures must be understood in order to carry out

maintenance and repair satisfactorily. When-

ever the owner has insufficient experience or

doubts as to his ability to do the work, all ad-

justments, maintenance, and repair should be

carried out only by qualified mechanics.

In order to perform the work efficiently and

to avoid costly mistakes, read the text, thor-

oughly familiarize yourself with the procedures

before starting work, and then do the work care-

fully in a clean area. Whenever special tools or

equipment are specified, do not use makeshift

tools or equipment. Precision measurements

can only be made if the proper instruments are

used, and the use of substitute tools may ad-

versely affect safe operation.

To get the longest life out of your motorcycle:

•

Follow the Periodic Maintenance Chart in the

Service Manual.

•

Be alert for problems and non-scheduled

maintenance.

•

Use proper tools and genuine Kawasaki mo-

torcycle parts. Special tools, gauges, and

testers that are necessary when servicing

Kawasaki Motorcycles are introduced by the

Service Manual. Genuine parts provided as

spare parts are listed in the Parts Catalog.

•

Follow the procedures in this manual care-

fully. Don’t take shortcuts.

•

Remember to keep complete records of main-

tenance and repair with dates and any new

parts installed.

How to Use this Manual

In this manual, the product is divided into

its major systems and these systems make up

the manual’s chapters. The Quick Reference

Guide shows you all of the product’s system

and assists in locating their chapters. Each

chapter in turn has its own comprehensive Ta-

ble of Contents.

For example, if you want ignition coil informa-

tion, use the Quick Reference Guide to locate

the Electrical System chapter. Then, use the

Table of Contents on the first page of the chap-

ter to find the Ignition Coil section.

Whenever you see these WARNING and

CAUTION symbols, heed their i nstructions!

Always follow safe operating and maintenance

practices.

WARNING

This warning symbol identifies special

instructions or procedures which, if not

correctly followed, could result in per-

sonal injury, or loss of life.

CAUTION

This caution symbol identifies special

instructions or procedures which, if not

strictly observed, could result in dam-

age to or destruction of equipment.

This manual contains four more symbols (in

addition to WARNING and CAUTION) which will

help you distinguish different types of informa-

tion.

NOTE

○

This note symbol ind icates points of par-

ticular interest for more efficient and con-

venient operation.

•

Indicates a procedural step or work to be

done.

○

Indicates a procedural sub-step or how to do

the work of the procedural step it follows. It

also precedes the text of a NOTE.

Indicates a conditional step or what action to

take based on the results of the test or inspec-

tion in the procedural step or sub-step it fol-

lows.

In most chapters an exploded view illustration

of the system components follows the Table of

Contents. In these illustrations you will find the

instructions indicating which parts require spec-

ified tightening torque, oil, grease or a locking

agent during assembly.

GENERAL INFORMATION 1-1

General Information

Table of Contents

Before Servicing ..................................................................................................................... 1-2

Model Identification................................................................................................................. 1-5

General Specifications............................................................................................................ 1-7

Technical Information.............................................................................................................. 1-13

Unit Conversion Table ............................................................................................................ 1-21

1-2 GENERAL INFORMATION

Before Servicing

Before starting to perform an inspection service or carry out a disassembly and reassembly opera-

tion on a motorcycle, read the precautions given below. To facilitate actual operations, notes, illustra-

tions, photographs, cautions, and detailed descriptions have been included in each chapter wherever

necessary. This section explains the items that require particular attention during the removal and

reinstallation or disassembly and reassembly of general parts.

Especially note the following:

(1) Dirt

Before removal and disassembly, clean the motor cycle. Any dirt entering the engine will shorten

the life of the motorcycle. For the same reason, before installing a new part, clean off any dust or

metal filings.

(2) Battery Ground

Disconnect the ground (–) cable from the battery before performing any disassembly operations

on the motorcycle. This prevents the engine from accidentally turning over while work is being

carried out, sparks from being generated while disconnecting the leads from electrical parts, as

well as damage to the electrical parts themselves. For reinstallation, first connect the positive

cable to the positive (+) terminal of the battery

(3) Installation, Assembly

Generally, installation or assembly is the reverse of removal or disassembly. However, if instal-

lation or assembly sequence is given in this Service Manual, follow it. Note parts locations and

cable, wire, and hose routing during removal or disassembly so they can be installed or assem-

bled in the same way. It is preferable to mark and record the locations and routing whenever

possible.

(4) Tightening Sequence

When installing bolts, nuts, or screws for which a tightening sequence is given in this Service

Manual, m ake sure to follow the sequence. When installing a part with several bolts, nuts, or

screws, start them all in their holes and tighten them to a snug fit, thus ensuring that the part has

been installed in its proper location. Then, tighten them to the specified torque in the tightening

sequence and method indicated. If tightening sequence instructions are not given, tighten them

evenly in a cross pattern. Conversely, to remove a part, first loosen all the bolts, nuts, or screws

that are retaining the part a 1/4-turn before removing them.

(5) Torque

When torque values are given in this Service Manual, use them. Either too little or too much

torque may lead to serious damage. Use a good quality, reliable torque wrench.

(6) Force

Common sense should dictate how much force is necessary in assembly and disassembly. If

a part seems especially difficult to remove or install, stop and examine what may be causing the

problem. Whenever tapping i s necessary, tap lightly using a wooden or plastic-faced mallet. Use

an impact driver for screws (particularly for the removing screws held by non-permanent locking

agent) in order to avoid damaging the screw heads.

(7) Edges

Watch for sharp edges, a s they could cause injury through careless handling, especially during

major engine disassembly and assembly. Use a clean piece of thick cloth when lifting the engine

or turning it over.

(8) High-Flash Point Solvent

A high-flash point solvent is recommended to reduce fire danger. A commercial solvent com-

monly available in North America is standard solvent (generic name). Always follow manufacturer

and container directions regarding the use of any solvent.

(9) Gasket, O-ring

Replace a gasket or an O-ring with a new part when disassembling. Remove any foreign matter

from the mating surface of the gasket or O-ring to ensure a perfectly smooth surface to prevent

oil or compression leaks.

(10)Liquid Gasket, Locking Agent

Clean and prepare surfaces where liquid gasket or non-permanent locking agent will be used.

Apply them sparingly. Excessive amount may block engine oil passages and cause serious dam-

age.

GENERAL INFORMATION 1-3

Before Servicing

(11)Press

When using a p ress or driver to install a part such as a wheel bearing, apply a small amount of

oil to the area where the two parts come in contact to ensure a smooth fit.

(12)Ball Bearing and Needle Bearing

Do not remove a ball bearing or a needle bearing unless it is absolutely necessary. Replace any

ball or needle bearings that were removed with new ones. Install bearings with the manufacturer

and size marks facing out, applying pressure evenly with a suitable driver. Apply force only to the

end of the race that contacts the press fit portion, and press it evenly over the base component.

(13)Oil Seal and Grease Seal

Replace any oil or grease seals that were removed with new ones, as removal generally dam-

ages seals. Oil or grease seals should be pressed into place using a suitable driver, applying a

force uniformly to the end of seal until the face of the seal is even with the end of the hole, unless

instructed otherwise. When pressing in an oil or grease seal which has manufacturer’s marks,

press it in w ith the marks facing out.

(14)Circlip, Retaining Ring, and Cotter Pin

When installing circlips and retaining rings, take care to compress or expand them only enough

to install them and no more. Install the circlip with its chamfered side facing load side as well.

Replace any circlips, retaining rings, and cotter pins that were removed with new ones, as re-

moval weakens and deforms them. If old ones are reused, they could become detached while

the motorcycle is driven, leading to a major problem.

(15)Lubrication

Engine wear is generally at its maximum while the engine is warming up and before all the sliding

surfaces have an adequate lubricative film. During assembly, make sure to apply oil to any sliding

surface or bearing that has been cleaned. Old grease or dirty oil could have lost its lubricative

quality and may contain foreign particles that act as abrasives; therefore, make sure to wipe it off

and apply fresh grease or oil. Some oils and greases in particular s hould be used only in certain

applications and may be harmful if used in an application for which they are not intended.

(16)Direction of Engine Rotation

To rotate the crankshaft manually, make sure to do so in the direction of positive rotation. Pos-

itive rotation is counterclockwise as viewed from the left side of the engine. To carry out proper

adjustment, it is furthermore necessary to rotate the engine in the direction of positive rotation as

well.

(17)Replacement Parts

When there is a replacement instruction, replace these parts with new ones every time they are

removed.

Replacement parts will be damaged or lose their original function once they are removed. There-

fore, always replace these parts with new ones every time they are removed. Although the pre-

viously mentioned gasket, O-ring, ball bearing, needle bearing, grease seal, oil seal, circlip, and

cotter pin have not been so designated in their respective text, they are replacement parts.

(18)Electrical Leads

All the electrical leads are either one-color or two-color. A two-color lead is identified first by

the primary color and then the stripe color. For example, a yellow lead with thin red stripes is

referred to as a “yellow/red” lead; it would be a “red/yellow” lead if the colors were reversed.

Unless instructed otherwise, electrical leads must be connected to leads of the same color.

Two-Color Electrical

1-4 GENERAL INFORMATION

Before Servicing

(19)Inspection

When parts have been disassembled, visually inspect these parts for the following conditions

or other damage. If there is any doubt as to the condition of them, replace them with new ones.

Abrasion

Crack

Hardening Warp

Bent Dent Scratch Wear

Color change Deterioration Seizure

(20)Specifications

Specification terms are defined as follows:

“Standards” show dimensions or performances which brand-new parts or systems have.

“Service Limits” indicate the usable limits. If the m easurement shows excessive wear or deteri-

orated performance, replace the damaged parts.

GENERAL INFORMATION 1-5

Model Identification

KX125-M1 Left Side View

KX125-M1 Right Side View

1-6 GENERAL INFORMATION

Model Identification

KX250-M1 Left Side View

KX250-M1 Right Side View

GENERAL INFORMATION 1-7

General Specifications

Items KX125-M1 KX125-M2 ∼ M3 KX125M6F ∼

Dimensions

Overall Length 2 155 mm (84.8 in.) 2 165 mm (85.2 in.)

Overall Width 825 mm (32.5 in.) 840 mm (33.1 in.) 815 mm (32.1 in.)

Overall H eight 1 200 mm (47.2 i n.) 1 265 mm (49.8 in.)

Wheelbase 1 455 mm (57.3 i n.) 1 470 mm (57.9 in.)

Road Clearance 340 mm (13.4 in.) ←

Seat Height 930 mm (36.6 in.) 940 mm (37.0 in.)

Dry Mass

87 kg (192 lb)

←

Curb Mass:

Front 45 kg (99 lb) ←

Rear 47 kg (104 lb) ←

Fuel Tank Capacity 8.2 L (2.2 US gal) ←

Engine

Type 2-stroke, single cylinder,

crankcase reed valve

←

Cooling System Liquid-cooled ←

Bore and Stroke 54.0 × 54.5 mm (2.13 × 2 .15 in.)

←

Displacement 124 cm³(7.6 cu in.) ←

Compression Ratio:

Low Speed 10.6 : 1 11.1 : 1 (EUR) 10.9 : 1

High Speed 8.1 : 1 8.5: 1(EUR)8.3: 1

Carburetion System Carburetor, MIKUNI TMX38χ ←

Starting System

Primary kick ←

Ignition System CDI ←

Ignition Timing 13° BTDC @9 710 r/min (rpm) 13° BTDC @9 710 r/min (rpm)

Spark Plug NGK BR9EIX NGK R6918B-9 NGK BR9ECMVX

Port Timing

Inlet:

Open

Full open ←

Close – –

Scavenging:

Open 64.9° BBDC ←

Close 64.9° ABDC ←

Exhaust:

Open 73.8° BBDC (low speed), ←

95.4° BBDC (high s peed) ←

Close 73.8° ABDC (low speed), ←

95.4° ABDC (high s peed)

←

Lubrication System

(Gasoline : Oil)

Petrol mix (32 : 1)

←

Drive Train

Primary Reduction

System:

Type

Gear

←

Reduction Ratio 3.200 (64/20) ←

1-8 GENERAL INFORMATION

General Specifications

Items KX125-M1 KX125-M2 ∼ M3 KX125M6F ∼

Clutch Type Wet, multi disc ←

Transmission:

Type 6-speed, constant mesh, return

shift

←

Gear Ratios:

1st 2.384 (31/13) ←

2nd 1.857 (26/14) ←

3rd 1.529 (26/17) ←

4th 1.294 (22/17) ←

5th 1.125 (27/24) ←

6th

1.000 (25/25)

←

Final Drive System:

Type Chain drive ←

Reduction Ratio 3.923 (51/13) ←

Overall Drive Ratio 12.553 @Top gear ←

Transmission Oil:

Grade API SE, SF or SG

←

API SH, SJ or SL with JASO MA ←

Viscosity SAE 10W-40 ←

Capacity 0.7L(0.74USqt) ←

Frame

Type Tubular, semi-double cradle ←

Steering Angle 45° to either side 42° to either side

Caster (rake angle) 27.5° 27°

Trail 100 mm (3.9 in.) 113mm(4.4in.)

Front Tire:

Size 80/100-21 51M ←

Make/Type DUNLOP, Tube type ←

Rear Tire:

Size 100/90-19 57M ←

Make/Type DUNLOP, Tube type ←

Rim Size:

Front 21 × 1.60 ←

Rear 19 × 1.85 ←

Front Suspension:

Type Telescopic fork (up side down) ←

Wheel Travel 300 mm (11.8 in.) ←

Rear Suspension:

Type Swingarm (Uni-trak) Swingarm (New Uni-trak)

Wheel Travel 310 mm (12.2 in.) ←

Brake Type:

Front and Rear Single disc ←

GENERAL INFORMATION 1-9

General Specifications

Items KX125-M1 KX125-M2 ∼ M3 KX125M6F ∼

Effective Disc Diameter:

Front 220 mm (8.7 in.) 225 m m (8.9 in.)

Rear 200 mm (7.9 in.) 215 mm (8.5 in.)

Specifications are subject to change without notice, and may not apply to every country.

(EUR): Europe Model

1-10 GENERAL INFORMATION

General Specifications

Items KX250-M1 KX250-M2

Dimensions

Overall Length 2 175 mm (85.6 in.) ←

Overall Width 825 mm (32.5 in.) 840 mm (33.1 in.)

Overall Height 1 205 mm (47.4 in.) 1 265 mm (49.8 in.)

Wheelbase

1 480 mm (58.3 in.)

←

Road Clearance 355 mm (14.0 in.) 340 mm (13.4 in.)

Seat Height 945 mm (37.2 in.) ←

Dry Mass 97 kg (214 lb) ←

Curb Mass:

Front 50 kg (110 lb) ←

Rear

51 kg (112 lb)

←

Fuel tank Capacity 8.2 L (2.2 US gal) ←

Engine

Type 2-stroke, single cylinder, piston

reed valve

←

Cooling System Liquid-cooled ←

Bore and Stroke 66.4 × 72.0 mm (2.61 × 2.85 in.) ←

Displacement 249 cm³ (15.25 cu in.) ←

Compression R atio

Low Speed

10.1 : 1 10.5 : 1

High Speed 8.6 : 1 8.8 : 1

Carburetion System Carburetor, KEIHIN PWK38S ←

Starting System Primary kick ←

Ignition System CDI ←

Ignition Timing 14° BTDC @7 740 r/min (rpm) ←

Spark Plug NGK BR8EIX

←

Port Timing:

Inlet:

Open Full open ←

Close – –

Scavenging:

Open 57.6° BBDC 59.3° BBDC

Close 57.6° ABDC 59.3° ABDC

Exhaust:

Open 78.1° BBDC (low speed), 78.4° BBDC (low speed),

91.4° BBDC (high speed) 92.2° BBDC (high speed)

Close 78.1° ABDC (low speed), 78.4° ABDC (low speed),

91.4° ABDC (high speed) 92.2° ABDC (high speed)

Lubrication System (Gasoline: Oil) Petrol mix (32 : 1) ←

Drive Train

Primary Reduction System:

Type Gear ←

Reduction ratio 3.000 (63/21) ←

Clutch Type

Wet, multi disc ←

GENERAL INFORMATION 1-11

General Specifications

Items KX250-M1 KX250-M2

Transmission:

Type 5 speed, constant mesh, return

shift

←

Gear Ratios:

1st 1.800 (27/15) ←

2nd 1.437 (23/16) ←

3rd 1.176 (20/17) ←

4th

1.000 (21/21)

←

5th 0.869 (20/23) ←

Final D rive System

Type Chain drive ←

Reduction Ratio 3.769 (49/13) ←

Overall Drive Ratio 9.832 @Top gear ←

Transmission Oil:

Grade API SE, SF or SG ←

API SH or SJ with JASO MA ←

Viscosity SAE 10W-40 ←

Capacity 0.85 L (0.90 US qt) ←

Frame

Type Tubular, semi-double cradle ←

Steering Angle 45° to either side 42° to either side

Caster (rake angle) 27° ←

Trail 97 mm (3.8 in.) 112mm(4.4in.)

Front Tire:

Size 80/100-21 51M ←

Make/Type BRIDGESTONE, Tube type ←

(EUR) DUNLOP, Tube type ←

Rear Tire:

Size 110/90-19 62M ←

Make/Type BRIDGESTONE, Tube type ←

(EUR) DUNLOP, Tube type ←

Rim Size:

Front 21 × 1.60 ←

Rear 19 × 2.15 ←

Front Suspension:

Type Telescopic fork (up side down) ←

Wheel Travel 300 mm (11.8 in.) ←

Rear Suspension:

Type Swingarm (Uni-trak) Swingarm (New Uni-trak)

Wheel Travel 310 mm (12.2 in.) ←

Brake Type:

Front and Rear Single disc ←

1-12 GENERAL INFORMATION

General Specifications

Items KX250-M1 KX250-M2

Effective Disc Diameter:

Front

220 mm (8.7 in.) 225 mm (8.9 in.)

Rear 200 mm (7.9 in.) 215 mm (8.5 in.)

Specifications are subject to change without notice, and may not apply to every country.

(EUR): Europe Model

GENERAL INFORMATION 1-13

Technical Information

Ratchet-Type Shift Mechanism (KX250M, KX125M)

○

The shift mechanism of the KX250M (5-speed) is shown in the following figure.

○

This mechanism is stronger and simpler than the usual slide type and enables light and positive

shifting. When the shift pedal [D] is applied, its turning force is transmitted almost directly to the

shift drum [E].

○

The mechanism has shorter length between the shift drum and the drive shaft, compared with the

previous model (for example, from 67 mm to 43.2 mm for KX125).

○

The shift force is transmitted as follows:

Shift Pedal → Shift Shaft [F] → Shift Mechanism Arm [G] → Ratchet [H] → Pawls [I], [M] in Ratchet

→ Shift Drum Cam [J] → Shift Forks → Gears

A. Top View

B. Front

C. Ratchet Plate

D. Shift Pedal

E. Shift Drum

F. To p View

G. Shift Mechanism Arm

H. Ratchet

I. Upper Pawls

J. Shift Drum Cam

K. Gear Set Lever

L. Return Spring Pin

M. Lower Pawl

N. Neutral Detent

O. Return Spring

1-14 GENERAL INFORMATION

Technical Information

○

This mechanism operates as follows:

1. Suppose the 1st gear position is set as shown.

Neutral Detent [N]

2. Shift Up (for example: shift from 1st to 2nd)

(→) : transmitting of shift force

The shift pedal is lifted. → The arm [G] turns counter-

clockwise until it stops at pin [L]. → ratchet [H] → lower

pawl [M] → shift drum cam [J] → shift drum → The gear

is shifted in 2nd position.

3. Ratchet Returns.

The arm [G] returns by force of spring [O]. → The ratchet

[H] disengages to be free by itself. → The set lever [K]

holds the shift drum cam [J]. → The ratchet [H] returns

(turns clockwise).

4. The 2nd Gear Position settles.

The upper and lower pawls [I], [M] catch the next teeth

inside the shift drum cam [J] → The ratchet [H] settles in

position. → The 2nd gear position settles.

5. Shift Down (for example: shift from 2nd to 1st)

The shift pedal is depressed. → The arm [G] turns clock-

wise until it stops at the pin [L]. → ratchet [H] → upper

pawl [I] → shift drum cam [J] → shift drum → The gear is

shifted into 1st position. → (continues to operate in the

samewayasShiftUp)

GENERAL INFORMATION 1-15

Technical Information

Chrome Composite Plating Cylinder (KX250M, KX125M)

○

This new cylinder bore [A] has Kawasaki’s compos-

ite cylinder plating, which is used for the first time on

two stroke engines. The composite plating includes a

nickel-phosphorous alloy, inorganic materials like ce-

ramic, silicone carbide and some organic materials.

○

The treatment improves heat transfer of the cylinder for

consistent power output, allows c loser piston-to-cylinder

clearances for more horsepower.

○

The treatment is porous, so it holds lubrication well, and

hard, so it resists abrasion and seizure.

○

This plating gets on well even the chamfered edge of the

cylinder top or port.

○

This improves the surface of the chamber at the top of

the cylinder, preventing hot spots, resultant pre-ignition

and other abnormal combustion in the chamber.

Previous Cylinder [A]

New C ylinder [B]

Exhaust Port [C]

Cylinder Top [D]

○

This enables the top end of the exhaust port from round

to straight in order to make gas flow smooth and improve

mid-high performance and extending piston ring life.

Previous Cylinder [A]

New C ylinder [B]

Exhaust Port [C]

1-16 GENERAL INFORMATION

Technical Information

KIPS (Kawasaki Integrated Power Valve System, KX250M, KX125M)

○

KIPS varies the exhaust port height to broaden the useful rpm range for low end and mid-range

without sacrificing the top end power (see ’95 KDX200H Service Manual for basic information about

KIPS).

○

KIPS is 2-stage-3-way type: the main exhaust port is opened earlier than the sub-exhaust ports

(2-stage) and they are opened differently in low, middle and high rpm (3-way).

(In low rpm)

resonator: open to fully, sub-exhaust ports and main exhaust port: close

(In middle rpm)

resonator: close, main exhaust port: open to fully, sub-exhaust ports open to halfway

(Inhighrpm)

resonator: close, main exhaust port and sub-exhaust ports open fully.

○

The KIPS valve is now made of aluminum instead of steel to save weight.

○

The KIPS main valve holder shape is modified to match the straightened exhaust port, and timing

for the main and sub-valves is changed to deliver more power in the low to mid-range.

○

The main valve end is changed from thick end to thin end, reducing exhaust pressure on the valve

and making valve operation smooth.

(KX250M)

A. Previous KIPS

B. New KIPS

GENERAL INFORMATION 1-17

Technical Information

(KX125M)

A. Previous KIPS

B. New Model

C. Full Opened Position

D. Low Speed Position

E. Straightened Exhaust Passage

○

The KIPS governor is modified so that the exhaust valves

operate over a wider rpm range to improve low and mid

-range power and smooth the power delivery.

○

The KX250’s governor inside is changed from straight to

concave in order to move the balls smoothly.

Previous Governor [A]

New Governor [B]

Carburetor (KX250M)

○

The 38.7 mm (1.524 in.) Keihin PWK 38S carburetor

helps boost mid-range and top-end power.

1-18 GENERAL INFORMATION

Technical Information

○

The crescent shaped slide [A] enables the needle to sit

closer to the intake ports for quicker throttle response.

○

Large bores in the front and back of the carburetor and

a smoother shape (38 to 40 mm-tapered bore [B]) boost

mixture flow for more mid-range and top-end power.

○

The semi air bleed needle jet [C] improves throttle re-

sponse in the very low and low range.

Front [D]

○

The air baffle forms vacuum, the stop narrows the outlet and speeds up outflow from the needle jet,

improving atomization.

←—: Fuel Droplets

← - -: Fuel Mist

A. Previous Carburetor

B. New Carburetor

C. Jet Needle

D. Air Baffle

E. Needle Jet

F. S t op

G. Engine Intake

GENERAL INFORMATION 1-19

Technical Information

H. Main Air

○

The new main air inlet tends to take in static pressure and to exclude dynamic pressure and vor-

texes, making the main air flow stable.

A. Previous Carburetor

B. New Carburetor

C. Jet Needle

D. Air Baffle

E. Main Air

F. Needle Jet

G. Engine Intake

Carburetor (KX125M)

○

The 38 mm (1.496 in.) Mikuni TMX 38-27 carburetor

helps boost mid-range and top-end power.

○

The arched slide [A] improves throttle response in the very

low and low ranges.

○

Large bores in the front and back of the carburetor and

a smoother shape (38 to 40 mm-tapered bore [B]) boost

mixture flow for more mid-range and top-end power.

○

The semi air bleed needle jet [C] improves throttle re-

sponse in the low range and provides proper mixture from

the low to top range.

Front [D]

○

In low range, fuel drops in the fuel/air mixture is larger and tends to stick to the carburetor wall.

The arched slide deflects fuel/air mixture flow from the wall to the middle of the carburetor for better

atomization and better throttle response.

1-20 GENERAL INFORMATION

Technical Information

A. Previous Carburetor

B. New Carburetor

C. Flat Slide (piston valve)

D. Arched Shape Slide (piston valve)

E. Engine Intake

○

The semi air bleed hole is positioned at the side of the needle jet, where fuel mixes w ith air well (due

to enough fuel and faster air flow than in main bore), resulting in better atomizing. The air screen

suppresses dynamic pressure around the main air inlet.

A. Previous Carburetor

B. New Carburetor

C. Jet Needle

D. Air Baffle

E. Main Air

F. Needle Jet

G. Engine Intake

H. Semi Air Bleed Hole

I. Air Screen

GENERAL INFORMATION 1-21

Unit Conversion Table

Prefixes for Units:

Prefix Symbol Power

mega M ×1000000

kilo k × 1 000

centi c ×0.01

milli m × 0.001

micro µ × 0.000001

Units o f Mass:

kg ×2.205=lb

g × 0.03527 = oz

Units of Volume:

L × 0.2642 = gal (US)

L × 0.2200 = gal (imp)

L × 1.057 = qt (US)

L × 0.8799 =

qt (imp)

L×2.113=

pint (US)

L × 1.816 = pint (imp)

mL × 0.03381 = oz (US)

mL × 0.02816 = oz (imp)

mL × 0.06102 = cu in

Units of Force:

N × 0.1020 = kgf

N × 0.2248 = lb

kgf × 9.807 = N

kgf × 2.205 = lb

Units of Length:

km × 0.6214 = mile

m × 3.281 = ft

mm × 0.03937 = in

Units of Torque:

N·m × 0.1020 = kgf·m

N·m × 0.7376 =

ft·lb

N·m × 8.851 = in·lb

kgf·m × 9.807 = N·m

kgf·m

×7.233=

ft·lb

kgf·m × 86.80 = in·lb

Units of Pressure:

kPa × 0.01020 = kgf/cm²

kPa × 0.1450 = psi

kPa × 0.7501 = cm Hg

kgf/cm²

× 98.07 = kPa

kgf/cm² × 14.22 = psi

cm Hg × 1.333 = kPa

Units o f Speed:

km/h × 0.6214 = mph

Units o f Power:

kW × 1.360 =

kW × 1.341 = HP

PS × 0.7355 = kW

× 0.9863 = HP

Units of Temperature:

PERIODIC MAINTENANCE 2-1

Periodic Maintenance

Table of Contents

Periodic Maintenance Chart ................................................................................................... 2-3

Torque and Locking Agent...................................................................................................... 2-5

Specifications ......................................................................................................................... 2-10

Special Tools .......................................................................................................................... 2-13

Periodic Maintenance Procedures.......................................................................................... 2-14

Fuel System......................................................................................................................... 2-14

Fuel Hose and Connection Check .................................................................................... 2-14

Throttle Grip Free Play Inspection .................................................................................... 2-14

Throttle Grip Free Play Adjustment................................................................................... 2-14

Idle Speed Inspection ....................................................................................................... 2-15

Idle Speed Adjustment...................................................................................................... 2-15

Air Cleaner Element Cleaning and Inspection .................................................................. 2-15

Fuel Tank and Tap Cleaning ............................................................................................. 2-16

Fuel Tap Inspection........................................................................................................... 2-17

Reed Valve Inspection ...................................................................................................... 2-17

Cooling System.................................................................................................................... 2-17

Coolant Level Inspection ................................................................................................... 2-17

Coolant Deterioration Inspection....................................................................................... 2-18

Coolant Draining ............................................................................................................... 2-18

Coolant Filling ................................................................................................................... 2-19

Air Bleeding....................................................................................................................... 2-20

Cooling Hoses and Connections Inspection ..................................................................... 2-20

Engine Top End ................................................................................................................... 2-20

Cylinder Head Warp Inspection ........................................................................................ 2-20

Cylinder Wear Inspection.................................................................................................. 2-21

Piston Diameter Measurement ......................................................................................... 2-21

Piston/Cylinder Clearance ................................................................................................ 2-22

Piston Ring, Piston Ring Groove Inspection ..................................................................... 2-23

Piston Ring End Gap Inspection ....................................................................................... 2-24

Piston, Piston Pin, Connecting Rod Wear Inspection ....................................................... 2-24

Exhaust Valve Clean and Inspect ..................................................................................... 2-25

Exhaust System ................................................................................................................ 2-25

Muffler Baffle Change ....................................................................................................... 2-26

Engine Right Side ................................................................................................................ 2-26

Clutch Lever Free Play Check .......................................................................................... 2-26

Clutch Lever Free Play Adjustment .................................................................................. 2-27

Friction and Steel Plates Wear, Damage Inspection......................................................... 2-27

Friction and Steel Plate Warp Inspection.......................................................................... 2-28

Engine Bottom End/Transmission ....................................................................................... 2-28

Transmission Oil Level Inspection .................................................................................... 2-28

Transmission Oil Change.................................................................................................. 2-29

Wheel/Tires.......................................................................................................................... 2-29

Air Pressure Inspection/Adjustment.................................................................................. 2-29

Tires Inspection.................................................................................................................2-30

Spoke Tightness Inspection.............................................................................................. 2-31

Rim Runout Inspection ...................................................................................................... 2-31

2-2 PERIODIC MAINTENANCE

Wheel Bearing Inspection ................................................................................................. 2-31

Final Drive............................................................................................................................ 2-32

Drive Chain Slack Inspection ............................................................................................ 2-32

Drive Chain Slack Adjustment .......................................................................................... 2-32

Drive Chain Wear Inspection ............................................................................................ 2-33

Drive Chain Lubrication..................................................................................................... 2-34

Sprocket Wear Inspection................................................................................................. 2-34

Rear Sprocket Warp Inspection ........................................................................................ 2-35

Brakes.................................................................................................................................. 2-35

Brake Lever Play Adjustment............................................................................................ 2-35

Brake Fluid Level Inspection............................................................................................. 2-36

Brake Fluid Change .......................................................................................................... 2-37

Brake Pad Wear Inspection .............................................................................................. 2-38

Brake Master Cylinder Cup and Dust Seal Replacement ................................................. 2-38

Caliper Fluid Seal and Dust Seal Replacement................................................................ 2-39

Brake Hose and Connection Check.................................................................................. 2-39

Suspension.......................................................................................................................... 2-39

Front Fork Oil Leak Inspection.......................................................................................... 2-39

Front Fork Oil Change/Oil Level Adjustment (each fork leg) ............................................ 2-40

Rear Shock Absorber Oil Change..................................................................................... 2-42

Uni-Trak Linkage Inspection ............................................................................................. 2-42

Chain Guide Wear Inspection ........................................................................................... 2-43

Chain Slipper Wear Inspection ......................................................................................... 2-43

Steering ............................................................................................................................... 2-43

Steering Inspection ........................................................................................................... 2-43

Steering Adjustment ......................................................................................................... 2-43

Stem Bearing Lubrication.................................................................................................. 2-46

Frame .................................................................................................................................. 2-46

Frame Inspection .............................................................................................................. 2-46

Electrical System ................................................................................................................. 2-47

Spark Plug Cleaning and Inspection................................................................................. 2-47

Spark Plug Gap Inspection ............................................................................................... 2-47

General Lubrication ............................................................................................................. 2-48

Lubrication ........................................................................................................................ 2-48

Nut, Bolt, and Fastener Tightness ....................................................................................... 2-49

Tightness Inspection ......................................................................................................... 2-49

PERIODIC MAINTENANCE 2-3

Periodic Maintenance Chart

The maintenance must be done in accordance with this chart to k eep the motorcycle in good running

condition.

FREQUENCY

OPERATION

After

each

race or

2.5 hr

Every

3 races

or 7.5

Every

5 races

or 12.5

Every

races

or 25 hr

As re-

quired

See

Page

Spark plug - clean, gap †

•

R 2-47

Clutch - adjust

•

2-26

Clutch and friction plates - inspect †

•

R 2-27

Throttle cable - adjust

•

2-14

Air cleaner element - clean

•

2-15

N Air cleaner element - replace If damaged 2-15

Carburetor - inspect and adjust

•

2-15

Transmission oil - change

•

2-28

G Piston and piston ring - clean and inspect†

•

R 2-21

Cylinder head, cylinder - inspect

•

2-20

Small end bearing - inspect †

•

R 2-24

I Reed valve - inspect †

•

2-17

Exhaust valve - clean and inspect

•

2-25

Exhaust pipe O-ring - replace

•

2-25

N Muffler - clean and inspect †

•

2-25

Muffler baffle - change

•

2-25

Kick pedal and shift pedal - clean

•

–

E Engine sprocket - inspect †

•

2-34

Coolant - check †

•

R 2-17

Cooling hoses and connections - inspect †

•

2-20

Brake adjustment - inspect †

•

2-35

C Brake pad wear - inspect †

•

2-38

Brake fluid level - inspect †

•

2-36

H Brake fluid - change Every 2 years 2-37

Brake master cylinder cup and dust cover -

replace

Every 2 years 2-38

Brake caliper fluid seal and dust seal -

replace

Every 2 years 2-39

S Brake hoses and pipe - replace Every 4 years 2-39

Brake hoses, connections - inspect †

•

2-39

S Spoke tightness and rim runout - inspect †

•

2-31

Wheel bearing - inspect †

•

2-31

I Drive chain - adjust

•

2-32

Drive chain - lubricate

•

2-34

S Drive chain wear - inspect †

•

2-33

Chain slipper and guide - replace If damaged

2-43

Rear sprocket - inspect †

•

2-35

2-4 PERIODIC MAINTENANCE

Periodic Maintenance Chart

FREQUENCY

OPERATION

After

each

race or

2.5 hr

Every

3 races

or 7.5

Every

5 races

or 12.5

Every

races

or 25 hr

As re-

quired

See

Page

Front fork - inspect and clean

•

2-39

Front fork oil - change 1st time after 2 races, then every 5 races 2-40

Rear shock oil - replace 1st time after 2 races, then every 5 races 2-42

C Fuel system - clean

•

2-16

H Fuel hose - replace Every 4 years 2-14

A Fuel hose, connections - inspect †

•

2-14

S Steering play - inspect †

•

2-43

S Steering stem bearing - grease

•

2-46

Swing arm and Uni-Trak linkage pivots -

grease

•

2-42

Swing arm and Uni-Trak linkage pivots -

inspect †

•

2-42

Wheel/tire (air pressure, excessive wear or

damage) - inspect

•

2-29

Frame - clean and inspect

•

2-46

Nuts, bolts, fasteners - inspect †

•

2-49

General lubrication - perform

•

2-48

†: Replace, add, adjust, clean or torque if necessary.

R: Replace

PERIODIC MAINTENANCE 2-5

Torque and Locking Agent

Tighten all bolts and nuts to the proper torque using an accurate torque wrench. If insufficiently

tightened, a bolt or nut may become damaged, strip an internal thread, or break and then fall out. The

following table lists the tightening toque for the major bolts and nuts, and the parts requiring use of a

non-permanent locking agent or liquid gasket.

When checking the tightening toque of the bolts and nuts, first loosen the bolt or nut by half a turn

and then tighten to specified torque.

Letters used in the “Remarks” column mean:

L : Apply a non-permanent locking agent to the threads.

LG : Apply liquid gasket to the threads.

S : Tighten the fasteners following the s pecified sequence.

Torque

Fastener

N·m kgf·m ft·lb

Remarks

Fuel System

Carburetor Holder Mounting Bolts

8.8 0.9 78 in·lb

Carburetor Holding Clamp Screw 1.5 0.15 13 in·lb

Reed Valve Screws 1.0 0.1 8.8 in·lb

Carburetor Top Cover Screws (KX125) 3.0 0.3 26 in·lb

Carburetor Top Cover Allen B olts (KX250) 3.9 0.4 35 in·lb

Throttle Sensor Bolt (KX250) 2.0 0.2 17 in·lb

Rear Frame Mounting Bolts 34 3.5 25

Air Cleaner Duct Clamp Screw 1.5 0.15 13 in·lb

Fuel Tap Plate Mounting Screws 0.8 0.08 7in·lb

Air Cleaner Duct Nuts

3.0 0.3 26 in·lb

Air Cleaner Housing Bolts 8.8 0.9 78 in·lb

Cooling System

Water Pump Cover Bolts 8.8 0.9 78 in·lb

Water Pump Impeller Bolt 6.9 0.7 61 in·lb

Cooling Hose Clamp Screws 1.5 0.15 13 in·lb

Coolant Drain Plug (Water Pump Cover) 8.8 0.9 78 in·lb

Coolant Drain Plug (Cylinder) (KX250) 8.8 0.9 78 in·lb

Cooling Hose Elbow Fitting Bolts (Cylinder) (KX250) 8.8 0.9 78 in·lb

Water Pump Cover Fitting Bolts (KX250)

5.9 0.6 52 in·lb

Radiator Shroud Bolts 8.8 0.9 78 in·lb

Radiator Mounting Bolts 8.8 0.9 78 in·lb

Radiator Screen Bolts

8.8 0.9 78 in·lb

Radiator Bracket Bolts 8.8 0.9 78 in·lb

Engine Top End

Main Valve Cover Bolts 5.9 0.6 52 in·lb

Cylinder Head Nuts 25 2.5 18 S

Spark Plug 26.5 2.75 19.5

Engine Mounting Bracket Nuts:

Engine Side 10 mm (KX125/250-M1) 44 4.5 33

Engine Side 10 mm (KX125/250-M2 ∼) 49 5.0 36

Frame Side 8 m

29 3.0 22

2-6 PERIODIC MAINTENANCE

Torque and Locking Agent

Torque

Fastener

N·m kgf·m ft·lb

Remarks

KIPS Cover Bolts:

KX125-M1 4.9 0.5 43 in·lb

KX125-M2 ∼ 8.8 0.9 78 in·lb

KX250 2.9 0.3 26 in·lb

Cylinder Nuts:

KX125 25 2.5 18.0

KX250 34 3.5 25

Main Lever Mounting Allen Bolt 3.9 0.4 35 in·lb L

Governor Shaft Lever Mounting Bolt (KX125) 6.9 0.7 61 in·lb

Exhaust Valve Retaining Bolts (KX125) 5.9 0.6 52 in·lb

Main Shaft Stopper Pin Plug (KX125) 0.8 0.08 6.9 in·lb

Main Valve Retaining Bolts (KX250) 5.9 0.6 52 in·lb

Operating Rod Retaining Screw (KX250)

5.4 0.55 48 in·lb

Operating Rod Left Side Plug (KX250) 22 2.2 16

Main Valve Rod Cover Screw (KX250) 5.9 0.6 52 in·lb

Coolant Drain Plug (Cylinder) (KX250) 8.8 0.9 78 in·lb

Inner Pipe Mounting Bolts 8.8 0.9 78 in·lb L

Muffler Pipe Mounting Bolts 8.8 0.9 78 in·lb L

Muffler Damper Mounting Bolts (KX125/250-M2 ∼) 8.8 0.9 78 in·lb

Expansion Chamber Mounting Bolt (KX125/250-M2 ∼) 12 1.2 8.7

Muffler Mounting B olt 8.8 0.9 78 in·lb

Engine Right Side

Clutch Hub Nut 98 10 72

Clutch Spring Bolts 8.8 0.9 78 in·lb

Clutch Cover Bolts 8.8 0.9 78 in·lb

Governor Shaft Lever Positioning Plug 0.6 0.06 5in·lb

Oil Filler Cap 1.5 0.15 13 in·lb

Right Engine Cover Bolts

8.8 0.9 78 in·lb

Generator Shaft Lever Mounting Bolt (KX125) 6.9 0.7 61 in·lb

Exhaust Valve Advancer Lever Mounting Allen Bolts 3.9 0.4 35 in·lb L

Primary Gear Nut (KX125)

59 6.0 43

Gear Set Lever Nut 8.8 0.9 78 in·lb

Ratchet Plate Mounting Bolts 8.8 0.9 78 in·lb

Kick Ratchet Guide Bolt

8.8 0.9 78 in·lb

Kick Pedal Bolt:

KX125 12 1.2 8.7

KX250 25 2.5 18

Shift Pedal Bolt 9.8 1.0 87 in·lb

External Shift Mechanism Return Spring Pin (KX250) 42 4.3 31 L

Gear Set Lever Pivot Stud – – – L (Planted

Side)

PERIODIC MAINTENANCE 2-7

Torque and Locking Agent

Torque

Fastener

N·m kgf·m ft·lb

Remarks

Engine Removal/Installation

Engine Mounting Nuts:

KX125/250-M1 44 4.5 33

KX125/250-M2 ∼ 49 5.0 36

Engine Mounting Bracket Nuts:

Engine Side 10 mm (KX125/250-M1) 44 4.5 33

Engine Side 10 mm (KX125/250-M2 ∼) 49 5.0 36

Frame Side 8 mm 29 3.0 22

Swing Arm Pivot Shaft Nut 98 10.0 72

Engine Bottom End/Transmission

Output Shaft Bearing Retaining Screws 5.4 0.55 48 in·lb L

Shift Drum Bearing Retaining Screws (KX125-M1) 6.4 0.65 56 in·lb L

Shift Drum Bearing Retaining Bolts (KX125-M2 ∼) 8.8 0.9 78 in·lb L

Shift Drum Bearing Retaining Bolts (KX250) 8.8 0.9 78 in·lb L

Drive Shaft Bearing Retaining Bolts (KX250) 8.8 0.9 78 in·lb

Engine Oil Drain Plug

20 2.0 14.5

Crankcase Bolts 8.8 0.9 78 in·lb

Flywheel Bolt (KX125) 22 2.2 16

Flywheel Nut (KX250) 78 8.0 58

Shift Drum Operating Cam Bolt 24 2.4 17 L

Cylinder Stud – – – L (Planted

Side)

Wheels/Tires

Front Axle Nut 78 8.0 58

Front Axle Clamp Bolts 20 2.0 14.5

Rear Axle Nut 108 11.0 80

Spoke Nipple

2.2 or

0.22 or

19 in·lb or

Final Drive

Rear Axle Nut 108 11.0 80

Rear Sprocket Nuts

34 3.5 25

Engine Sprocket Cover Bolts 4.9 0.5 43 in·lb

Brakes

Front Master Cylinder Clamp Bolts

8.8 0.9 78 in·lb

Brake Lever Pivot Bolt 5.9 0.60 52 in·lb

Brake Lever Pivot Bolt Locknut 5.9 0.60 52 in·lb

Brake Hose Banjo Bolts 25 2.5 18

Brake Pad Bolt 18 1.8 13

Caliper Bleed Valves (Front, Rear) 7.8 0.8 69 in·lb

Caliper Mounting Bolts (Front)

25 2.5 18

Rear Master Cylinder Mounting Bolts 9.8 1.0 87 in·lb

Rear Master Cylinder Push Rod Locknut 18 1.8 13.0

2-8 PERIODIC MAINTENANCE

Torque and Locking Agent

Torque

Fastener

N·m kgf·m ft·lb

Remarks

Brake Disc Mounting Bolts:

Front 9.8 1.0 87 in·lb L

Rear 23 2.3 16.6 L

Caliper Holder Bolt

27 2.8 20

Rear Brake Pad Bolt Plug 2.5 0.25 22 in·lb

Brake Pedal Mounting Bolt 25 2.5 18

Suspension

Front Fork Top Plug 29 3.0 22

Front Fork Clamp Bolts (Upper, Lower) 20 2.0 14.5

Push Rod Nut 28 2.9 21

Front Axle Clamp Bolts 20 2.0 14.5

Front Fork Cylinder Valve Assembly 54 5.5 40 L

Swingarm Pivot Shaft Nut 98 10.0 72

Tie-Rod Mounting Nut (Front, Rear) 83 8.5 61

Rocker Arm Pivot Nut 83 8.5 61

Rear Shock Absorber Mounting Nuts:

Upper 39 4.0 29

Lower 34 3.5 25

Steering

Steering Stem Head Nut 98 10 72

Steering Stem Locknut 4.9 0.5 43 in·lb

Handlebar Clamp Bolts 25 2.5 18

Front Fork Clamp Bolts (Upper, Lower) 20 2.0 14.5

Electrical System

Flywheel Bolt 22 2.2 16

Flywheel Nut 78 8.0 58

Stator Plate Mounting Screws 4.4 0.45 39 in·lb

Spark Plug 26.5 2.75 19.5

Magneto Cover Bolts: (KX125/250-M1) 4.9 0.5 43 in·lb

Magneto Cover Bolts: KX125/250-M2∼) 3.9 0.4 35 in·lb

C.D.I Unit Mounting Bolts

8.8 0.9 78 in·lb

Ignition Coil Mounting Bolts 8.8 0.9 78 in·lb

PERIODIC MAINTENANCE 2-9

Torque and Locking Agent

Basic Torque for General Fasteners

Torque

Threads dia. (mm)

N·m kgf·m ft·lb

5 3.4 ∼ 4.9 0.35 ∼ 0.50 30 ∼ 43 in·lb

6 5.9 ∼ 7.8 0.60 ∼ 0.80 52 ∼ 69 in·lb

8 14 ∼ 19 1.4 ∼ 1.9 10.0 ∼ 13.5

10 25 ∼ 34 2.6 ∼ 3.5 19.0 ∼ 25

12 44 ∼ 61 4.5 ∼ 6.2 33 ∼ 45

14 73 ∼ 98 7.4 ∼ 10.0 54 ∼ 72

16 115 ∼ 155 11.5 ∼ 16.0 83 ∼ 115

18 165 ∼ 225 17.0 ∼ 23.0 125 ∼ 165

20 225 ∼ 325 23 ∼ 33 165 ∼ 240

2-10 PERIODIC MAINTENANCE

Specifications

Item Standard Service Limit

Fuel System

Throttle Grip Free Play 2 ∼ 3 mm (0.08 ∼ 0.12 in.) –––

Air Cleaner Element Oil High quality foam air filter oil –––

Read Valve Warp 0.5 mm (0.020 in.)

Cooling System

–––

Coolant:

Type (recommended) Permanent type antifreeze

Color Green

Mixed Ratio Soft water 50% and coolant 50%

Freezing Point –35°C (–31°F)

Total Amount:

KX125 0.97 L (1.02 US qt)

KX250 1.20 L (1.27 US qt)

Engine Top End

Cylinder Head Warp ––– 0.03 mm (0.0012 in.)

Cylinder, Piston (KX125):

Cylinder Inside Diameter (15 mm

(0.59 in.) below of the cylinder

head)

54.010 ∼ 54.025 mm

(2.1264 ∼ 2.1270 in.)

54.10 mm (2.130 in.)

Piston Diameter 53.955 ∼ 53.970 mm

(2.1242 ∼ 2.1480 in.)

53.81 mm (2.118 in.)

Piston/Cylinder Clearance 0.040 ∼ 0.070 mm (0.0016 ∼ 0.0028 in.) –––

Piston Ring/Groove clearance 0.015 ∼ 0.050 mm (0.0006 ∼ 0.0020 in.) 0.15 mm (0.006 in.)

Piston Ring Groove Width 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.) 1.11 mm (0.044 in.)

Piston Ring Thickness 0.980 ∼ 0.995 mm (0.0386 ∼ 0.0392 in.) 0.91 mm (0.036 in.)

Piston Ring End Gap 0.35 ∼ 0.55 mm (0.0138 ∼ 0.0217 in.) 0.85 mm (0.033 in.)

Piston Pin Diameter 14.995 ∼ 15.000 mm

(0.5904 ∼ 0.5906 in.)

14.96 mm (0.589 in.)

Piston Pin Hole Diameter 15.001 ∼ 15.011 mm

(0.5906 ∼ 0.5910 in.)

15.08 mm (0.594 in.)

Small End Inside Diameter

19.003 ∼ 19.014 mm

(0.7481 ∼ 0.7486 in.)

19.05 mm (0.750 in.)

Cylinder, Piston (KX250):

Cylinder Inside Diameter (30 mm

(1.18 in.) below of the cylinder

Head)

66.400 ∼ 66.415 mm

(2.6142 ∼ 2.6148 in.)

66.46 mm (2.617 in.)

Piston Diameter 66.336 ∼ 66.351 mm

(2.6116 ∼ 2.6122 in.)

66.19 mm

(2.6059 in.)

Piston/Cylinder Clearance 0.049 ∼ 0.079 mm (0.0019 ∼ 0.0031 in.) –––

Piston Ring/Groove Clearance 0.025 ∼ 0.06 mm

(0.00098 ∼ 0.00236 in.)

0.16 mm (0.006 in.)

Piston Ring Groove Width 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.) 1.11 mm (0.044 in.)

Piston Ring Thickness

0.970 ∼ 0.985 mm (0.0382 ∼ 0.0388 in.) 0.90 mm (0.035 in.)

Piston Ring End Gap 0.25 ∼ 0.45 mm (0.0098 ∼ 0.0177 in.) 0.75 mm (0.030 in.)

Piston Pin Diameter 17.995 ∼ 18.000 mm

(0.7085 ∼ 0.7087 in.)

17.96 mm (0.707 in.)

PERIODIC MAINTENANCE 2-11

Specifications

Item Standard Service Limit

Piston Pin Hole Diameter 18.001 ∼ 18.011 mm

(0.7087 ∼ 0.7091 in.)

18.08 mm (0.712 in.)

Small End Inside Diameter

22.003 ∼ 22.012 mm

(0.8663 ∼ 0.8666 in.)

22.05 mm (0.868 in.)

Engine Right Side

Clutch Lever Free Play 2 ∼ 3 mm (0.08 ∼ 0.12 in.) –––

Friction Plate Thickness

KX125 2.72 ∼ 2.88 mm (0.107 ∼ 0.113 in.) 2.6 mm (0.102 in.)

KX250 2.92 ∼ 3.08 mm (0.115 ∼ 0.121 in.) 2.8mm(0.110in.)

Steel Plate Thickness:

KX125

1.5 ∼ 1.7 mm (0.059 ∼ 0.067 in.) 1.4 mm (0.055 in.)

KX250 1.46 ∼ 1.74 mm (0.057 ∼ 0.069 in.) 1.36 mm (0.054 in.)

Friction Plate Warp 0.15 mm (0.006 in.) or Less 0.3 mm (0.012 in.)

Steel Plate Warp 0.2 mm (0.008 in.) or Less 0.3 mm (0.012 in.)

Engine Bottom End/Transmission

Transmission Oil:

Grade API SE, SF or SG

API SH, SJ or SL with JASO MA

Viscosity SAE 10W-40

Capacity:

KX125 0.7 L (0.74 US qt)

KX250 0.85 L (0.90 US qt) –––

Wheels/Tires

Rim Runout (with tire installed):

Axial 1.0 mm (0.04 in.) or less 2 mm (0.08 in.)

Radial 1.0 mm (0.04 in.) or less 2 mm (0.08 in.)

Final Drive

DriveChainSlack 52 ∼ 62 mm (2.05 ∼ 2.44 in.) –––

Drive Chain 20 Link Length 317.5 ∼ 318.2 mm (12.50 ∼ 12.53 in.) 323 mm (12.72 in.)

Rear Sprocket Warp 0.4 mm (0.016 in.) or less 0.5 mm (0.020 in.)

Brakes

Brake Lever Play Adjustable (to suit rider) –––

Brake Fluid:

Type:

Front

DOT3 or DOT4

–––

Rear DOT4 –––

Brake Pad Lining Thickness:

Front

3.8 mm (0.150 in.) 1 mm (0.04 in.)

Rear 6.4 mm (0.252 in.) 1 mm (0.04 in.)

Suspension

Fork Oil:

Oil Viscosity KHL15-10 (KAYABA 01) or equivalent

2-12 PERIODIC MAINTENANCE

Specifications

Item Standard Service Limit

Oil Capacity (par unit):

KX125-M1 652±4mL(22.04±0.14USoz.) –––

KX125-M2 ∼ 565±4mL(19.10±0.14USoz.) –––

KX250-M1 664±4mL(22.45±0.14USoz.) –––

KX250-M2 ∼

578±4mL(19.54±0.14USoz.)

–––

Oil Level (fully compressed,

spring removed):

(Adjustable range)

KX125-M1

135 ±2 mm (5.31 ±0.08 in.)

100 ∼ 145 mm

KX125-M2 ∼ 105 ±2 mm (4.13 ±0.08 in.) 70 ∼ 120 mm

KX250-M1 125 ±2 mm (4.92 ±0.08 in.) (3.94 ∼ 5.71 in.)

KX250-M2 ∼ 88 ±2 mm (3.46 ±0.08 in.) (2.76 ∼ 4.72 in.)

Electrical System

Spark Plug Gap 0.7 ∼ 0.8 mm (0.028 ∼ 0.031 in.) –––

PERIODIC MAINTENANCE 2-13

Special Tools

Steering Stem Nut Wrench:

57001-1100

Jack:

57001-1238

Fork Piston Rod Puller, M1 2 × 1.25:

57001-1289

Fork Oil Level Gauge:

57001-1290

2-14 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Fuel System

Fuel Hose and Connection Check

○

The fuel hoses are designed to be used throughout the

motorcycle’s life without any maintenance, however, if the

motorcycle is not properly handled, the inside the fuel line

can cause fuel to leak [A] or the hose to burst. Remove

the fuel tank and check the fuel hose.

Replace the fuel hose if any fraying, cracks [B] or bulges

[C] are noticed.

•

Check that the hoses are securely c onnected and clamps

are tightened correctly.

•

When installing, route the hoses according to Cable,

Wire, and Hose Routing section in the Appendix chapter.

•

When installing the fuel hoses, avoid sharp bending, kink-

ing, flattening or twisting, and route the fuel hoses with a

minimum of bending so that the fuel flow will not be ob-

structed.

Replace the hose if i t has been sharply bent or kinked.

ThrottleGripFreePlayInspection

•

Check throttle grip free play [B] by lightly turning the throt-

tlegrip[A]backandforth.

If the free play is improper, adjust the throttle cable.

Throttle Grip Free Play

Standard: 2 ∼ 3 mm (0.08 ∼ 0.12 in.)

•

Check that the throttle grip moves smoothly from full open

to close, and the throttle closes quickly and completely in

all steering positions by the return spring.

If the throttle grip does not return properly, check the throt-

tle cable routing, grip free play, and cable damage. Then

lubricate the throttle cable.

•

Run the engine at the idle speed, and turn the handlebar

all the way to the right and left to ensure that the idle speed

does not change.

If the idle speed increase, check the throttle cable free

play and the cable routing.

ThrottleGripFreePlayAdjustment

•

Loosen the locknut [A] at the upper end of the throttle

cable.

•

Turn the adjuster [B] until the proper amount of throttle

grip free play is obtained.

•

Tighten the locknut.

PERIODIC MAINTENANCE 2-15

Periodic Maintenance Procedures

If the throttle grip free play cannot be adjusted with the

adjuster at the upper end of the throttle cable, use the

cable adjuster [A] at the carburetor.

•

Free the fuel cut valve connector from the frame.

•

Pull the boot off of the carburetor top. Make the necessary

free play adjustment at the lower cable adjuster, tighten

the locknut [B], and install the boot.

•

Turn the handlebar from side to side while idling the en-

gine. If idle speed varies, the throttle cable m ay be poorly

routed or it may be damaged.

WARNING

Operation with an improperly adjusted, incorrectly

routed, or damaged cable could result in an unsafe

riding condition.

Idle Speed Inspection

•

Start the engine and warm it up thoroughly.

•

With the engine idling, turn the handlebar to both sides.

If handlebar movement changes the idle speed, the throt-

tle cable may be improperly adjusted or incorrectly routed,

or it may be damaged. Be sure to correct any of these

conditions before riding (see Cable, Harness, Hose Rout-

ing in the Appendix chapter).

WARNING

Operation with an improperly adjusted, incorrectly

routed, or damaged cable could result in an unsafe

riding condition.

•

Check idle speed.

Adjust it as needed.

Idle Speed Adjustment

•

First turn in the air screw [A] until it seats lightly, and back

it out the specified number of turns. (see specifications in

the Fuel System chapter)

•

Start the engine and warm it up thoroughly.

•

Turn the idle adjusting screw [B] to obtain desired idle

speed. If no idle is preferred, turn out the screw until the

engine stops.

•

Open and close the throttle a few times to make sure that

the idle speed is as desired. Readjust if necessary.

Air Cleaner Element Cleaning and Inspection

NOTE

○

In dusty areas, the element should be cleaned more

frequently than recommended interval.

○

After riding through rain or on muddy roads, the element

should be c leaned immediately.

○

Since repeated cleaning opens the pores of the ele-

ment, replace it with a new one in accordance with the

Periodic Maintenance Chart. Also, if there is a break in

the element material or any other damage to the ele-

ment, replace the element with a new one.

2-16 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

WARNING

Clean the element in a well-ventilated area, and take

care that there are no sparks or flame anywhere

near the working area; this includes any appliance

with a pilot light. Because of the danger of highly

flammable liquids, do not use gasoline or a low

flash-point solvent to clean the element.

•

Remove the air cleaner element, and separate the ele-

ment [A] from the frame [B].

•

Clean the element in a bath of a high-flash point solvent

using a soft bristle brush. S queeze it dry in a clean towel.

Do not wring the element or blow it dry; the element can

be damaged.

•

Check all the parts of the element for visible damage.

If any of the parts of the element are damaged, replace

them.

•

After cleaning, saturate the element with a high-quality

foam-air-filter oil, squeeze out the excess, t hen wrap it in

a clean rag and squeeze it as dry as possible. Be careful

not to tear the sponge filter.

•

Assemble the element.

•

Remove the towel from the carburetor.

•

Install the element.

Fuel Tank and Tap Cleaning

WARNING

Clean the fuel tank in a w ell-ventilated area, and

take care that there is no sparks or flame anywhere

near the working area. Because of the danger of

highly flammable liquids, do not use gasoline or low

flash-point solvent to clean the tank.

•

Remove the fuel tank and drain it.

•

Pour some high-flash point solvent into the fuel tank and

shake the tank to remove dirt and fuel deposits.

•

Pour the solvent out of the tank.

•

Remove the fuel tap from the tank by taking out the bolts.

•

Clean the fuel tap filter screen in a high-flash point sol-

vent.

•

Pour high-flash point solvent through the tap in all lever

positions.

•

Dry the tank and tap with compressed air.

•

Install the tap in the fuel tank.

•

Install the fuel tank.

PERIODIC MAINTENANCE 2-17

Periodic Maintenance Procedures

Fuel Tap Inspection

•

Remove the fuel tap.

•

Check the fuel tap filter screen [A] for any breaks or dete-

rioration.

If the fuel tap screen have any breaks or is deteriorated, it

may allow dirt to reach the carburetor, causing poor run-

ning. Replace the fuel tap.

If the fuel tap leaks, or allows fuel to flow when it is at OFF

position, replace the damaged O-ring [B].

Reed Valve Inspection

•

Inspect the reeds for cracks, folds, or other visible dam-

age.

If there is any doubt as to the condition of a reed, replace

the reed valve part with a new one.

If a reed becomes wavy, replace the valve part with a new

one even if its warp is less than the service limit.

•

Measure the clearance between the reed [A] and holder

[B], and check the reed warp as shown.

If any one of the clearance measurements exceeds the

service limit, replace the damaged valve parts with a new

one.

Reed Warp

Service Limit: 0.5 mm (0.020 in.)

Cooling System

Check the coolant level each day before riding the motor-

cycle, and replenish coolant if the level is low. Change the

coolant in accordance with the Periodic Maintenance C hart.

WARNING

To avoid burns, do not remove the radiator cap

or try to inspect the coolant level or change the

coolant when the engine is still hot. Wait until it

cools down.

Coolant Level Inspection

NOTE

○

Check the level when the engine is cold (room or ambi-

ent temperature).

•

Situate the motorcycle so that it is perpendicular to the

ground.

•

Remove the radiator cap [A].

NOTE

○

Remove the radiator cap in two steps. First turn the

cap counterclockwise to the first stop and wait there for

a few seconds. Then push down and turn it further in

the same direction and remove the cap.

2-18 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

•

Check the coolant level. The coolant level [A] should be

at the bottom of the filler neck [B].

If the coolant level is low, add coolant through the filler

opening to the bottom of the filler neck. Install the cap.

Recommended coolant:

Permanent type of antifreeze (soft water and

ethylene glycol plus corrosion and rust inhibitor

chemicals for aluminum engines and radiators)

Water and coolant mixture ratio:

1:1(water50%,Coolant50%)

Total amount:

KX125: 0.97 L (1.02 US qt.)

KX250: 1.20 L (1.27 US qt.)

Coolant Deterioration Inspection

•

Visually inspect the coolant.

If whitish cotton-like wafts are observed, aluminum parts

in the cooling system are corroded. If the coolant is

brown, iron or steel parts are rusting. In either case, flush

thecoolingsystem.

If the coolant gives off an abnormal smell, check for a

cooling system leak. It may be caused by exhaust gas

leaking into the cooling system.

Coolant Draining

The coolant should be changed periodically to ensure

long engine life.

WARNING

To avoid burns, do not remove the radiator cap or

try to change the coolant when the engine is still

hot. Wait until it cools down.

Coolant on tires will make them slippery and can

cause an accident and injury. Immediately wipe up

or wash away any coolant that spills on the frame,

engine or other painted parts. Since coolant is

harmful to the human body, do not use for drinking.

PERIODIC MAINTENANCE 2-19

Periodic Maintenance Procedures

•

Remove the radiator cap.

NOTE

○

Remove the radiator cap in two steps. First turn the

cap counterclockwise to the first stop and wait there for

a few seconds. Then push down and turn it further in

the same direction and remove the cap.

•

Place a container under the coolant drain plug (KX125)

[A] or plugs (KX250) [B], and drain the coolant from the

radiator and engine by removing the drain plug on the

water pump cover and the cylinder (KX250). Immediately

wipe or wash out any coolant that spills on the frame,

engine, or wheel.

•

Inspect the old coolant for visual evidence of corrosion

and abnormal smell (see Coolant Deterioration Inspec-

tion).

Coolant Filling

CAUTION

Use coolant containing corrosion inhibitors made

specifically for aluminum engines and radiators in

accordance with the instruction of the manufac-

ture’s. Soft or distilled water must be used with the

antifreeze (see below for antifreeze) in the cooling

system. If hard water is used in the system, it

causes scale accumulation in the water passages,

and considerably reduces the efficiency of the

cooling system.

Recommended Coolant

Type:

Permanent type antifreeze (soft water

and ethylene glycol plus corrosion

and rust inhibitor chemicals for

aluminum engines and radiators)

Color: Green

Mixed ratio:

Soft water 50%, Coolant 50%

Freezing point:

−35°C (−31°F)

Total amount

KX125: 0.97 L (1.02 US qt.)

KX250: 1.20 L (1.27 US qt.)

•

Install the drain plug.

○

Replace the gasket with a new one.

•

Tighten:

Torque - Coolant Drain Plug on Water Pump Cover: 8.8 N·m

(0.9 kgf·m, 78 in·lb)

Coolant Drain Plug on Cylinder (KX250): 8.8 N·m

(0.9 kgf·m, 78 ft·lb)

2-20 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

•

Fill the radiator up to the bottom of the radiator filler neck

[B] with coolant [A], and install the cap, turning it clockwise

about 1/4 turn.

NOTE

○

Pour in the coolant slowly so that it can expel the air

from the engine and radiator. The radiator cap must be

installedintwosteps.Firstturnthecapclockwisetothe

first stop. Then push down on it and turn it the rest of

the way.

•

Check the cooling system for leaks.

Air Bleeding

Before putting the motorcycle into operation, any air

trapped in the cooling system must be removed as follows.

•

Start the engine, warm up the engine thoroughly, and then

stop the engine. Wait until the engine cools down.

•

Remove the radiator cap.

•

Check the coolant level.

If the coolant level is low, add coolant up to the bottom of

the filler neck.

•

Install the radiator cap.

•

Check the cooling system for leaks.

Cooling Hoses and Connections Inspection

○

The high pressure inside the cooling hose can cause

coolant to leak [A] or the hose to burst if the line is not

properly maintained. Visually inspect the hoses for signs

of deterioration. Squeeze the hoses. A hose should not

be hard and brittle, nor should it be soft or swollen.

Replace the hose if any fraying, cracks [B] or bulges [C]

are noticed.

•

Check that the hoses are securely c onnected and clamps

are tightened correctly.

Torque - Cooling Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,

13 in·lb)

Engine Top End

Cylinder Head Warp Inspection

•

Lay a straightedge [A] across the lower surface of the

head at several different points, and measure warp by

inserting a thickness gauge [B] between the straightedge

and the head.

If warp exceeds the service limit, repair the mating sur-

face. Replace the cylinder head if the mating surface is

badly damaged.

Cylinder Head Warp

Service Limit: 0.03 mm (0.0012 in.)

PERIODIC MAINTENANCE 2-21

Periodic Maintenance Procedures

Cylinder Wear Inspection

NOTE

○

Measure the cylinder inside diameter when the c ylinder

is cold (room or ambient temperature).

•

Visually Inspect the inside of the cylinder for scratches

and abnormal wear.

If the cylinder is damaged or badly worn, replace it with a

new one.

•

Since there is a difference in cylinder wear in different di-

rections, take a side-to-side and a front-to back measure-

ment shown in the figure.

If any of the c ylinder inside diameter measurements ex-

ceeds the service limit, the cylinder must be replaced with

a new one since the PLATING cylinder cannot be bored

or honed.

(A): KX125 - 15 mm (0.6 in.)

KX250 - 30 mm (1.2 in.)

Cylinder Inside Diameter

KX125:

Standard 54.010 ∼ 54.025 mm (2.1264 ∼ 2.1270

in.), and less than 0.01 mm (0.0004

in.) difference between any two

measurements.

Service Limit 54.10 mm (2.130 i n.), or more than

0.05 mm (0.020 in.) difference

between any two measurements.

KX250:

Standard 66.400 ∼ 66.415 mm (2.6142 ∼ 2.6148

in.), and less than 0.01 mm (0.0004

in.) difference between any two

measurements.

Service Limit 66.46 mm (2.617 i n.), or more than

0.05 mm (0.020 in.) difference

between any two measurements.

Piston Diameter Measurement

•

Measure the outside diameter of the piston 15.0 mm (0.59

in.) (KX125) or 20.5 mm (0.81 in.) (KX250) [A] up from

the bottom of the piston at a right angle to the direction of

the piston pin.

If the measurement is under the service limit, replace the

piston.

(A): KX 125 - 15.0 mm (0.59 in.)

KX250 - 20.5 mm (0.81 in.)

2-22 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Piston Diameter

KX125:

Standard: 53.955 ∼ 53.970 mm (2.1242 ∼ 2.1248

in.)

Service Limi t: 53.81 mm (2.118 in.)

KX250:

Standard: 66.336 ∼ 66.351 mm (2.6116 ∼ 2.6122

in.)

Service Limi t: 66.19 mm (2.606 in.)

Piston/Cylinder Clearance

The piston-to-cylinder clearance is measured whenever a

piston or cylinder is replaced with a new one. The standard

piston-to-cylinder clearance must be adhered to whenever

the cylinder is replaced.

If only a piston is replaced, the clearance may exceed the

standard slightly. But it must not be less than the minimum,

in order to avoid piston seizure.

The most accurate way to find the piston clearance is

by making separate piston and cylinder diameter measure-

ments and then computing the difference between the two

values. Measure the piston diameter as just described, and

measure the cylinder diameter at the very bottom of the

cylinder.

Piston/Cylinder Clearance

Standard:

KX125: 0.040 ∼ 0.070 mm (0.0016 ∼ 0.0028 in.)

KX250: 0.049 ∼ 0.079 mm (0.0023 ∼ 0.0031 in.)

PERIODIC MAINTENANCE 2-23

Periodic Maintenance Procedures

Piston Ring, Piston Ring Gro ove Inspection

•

Visually inspect the piston rings and the piston ring

grooves.

If the rings are worn unevenly or damaged, they must be

replaced.

If the piston ring grooves are w orn unevenly or damaged,

the piston must be replaced and fitted with new rings.

•

Check for uneven groove wear by inspecting the ring seat-

ing.

•

The rings should fit perfectly parallel to the groove sur-

faces. If not, the piston must be replaced.

•

With the piston ring in its groove, make several mea-

surements with a thickness gauge [A] to determine piston

ring/groove clearance.

If the clearance exceeds the service limit, measure the

thickness of the piston ring

If the ring has worn down to less than the service limit,

replace the ring; if the groove width exceeds the service

limit, replace the piston.

Piston Ring/Groove Clearance

KX125:

Standard: 0.015 ∼ 0.050 mm (0.00 06 ∼ 0.0020 in.)

Service L imit: 0.15 mm (0.0059 in.)

KX250:

Standard: 0.025 ∼ 0.060 mm (0.00 10 ∼ 0.0024 in.)

Service L imit: 0.16 mm (0.006 in.)

Piston Rin g Thickness

KX125:

Standard: 0.980 ∼ 0.995 mm (0.0386 ∼ 0.0392 in.)

Service L imit: 0.91 mm (0.036 in.)

KX250:

Standard: 0.970 ∼ 0.985 mm (0.0382 ∼ 0.0388 in.)

Service L imit: 0.90 mm (0.035 in.)

Piston Ring Groove Width

KX125:

Standard: 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.)

Service L imit: 1.11 mm (0.044 in.)

KX250:

Standard: 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.)

Service L imit: 1.11 mm (0.044 in.)

2-24 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Piston Ring End Gap Inspection

•

Place the piston ring [A] inside the cylinder [B], using the

piston to locate the ring squarely in place.

•

Set it close to the bottom of the cylinder, where cylinder

wear is low.

•

Measure the gap between the ends of the ring with a thick-

ness gauge [C]

If the gap is wider than the service limit, the ring is over-

worn and must be replaced.

Piston Ring End Gap

KX125:

Standard: 0.35 ∼ 0.55 mm (0.0138 ∼ 0.0217 in.)

Service Limit: 0.85 mm (0. 033 in.)

KX250:

Standard: 0.25 ∼ 0.45 mm (0.0098 ∼ 0.0177 in.)

Service Limit: 0.75 mm (0. 030 in.)

Piston, Piston Pin, Connecting Rod Wear Insp ection

•

Visually inspect the snap ring [A] still fitted in place.

If the ring shows weakness or deformation, replace the

ring. Also if the pin hole groove shows excessive wear,

replace the piston.

•

Measure the diameter of the piston pin [B] with a microm-

eter.

If the piston pin diameter is less than the s ervice limit at

any point, replace the piston pin.

•

Using a cylinder gauge, measure the diameter of both of

piston pin holes [C] in the piston and the inside diameter

of the c onnecting rod small end.

If either piston pin h ole diameter exceeds the service limit,

replace the piston.

If the connecting rod small end inside diameter exceeds

the service limit, replace the crankshaft assembly.

•

Check the needle bearing [D].

○

The rollers in a needle bearing normally w ear very little,

and wear is difficult to m easure. Instead of measuring, in-

spect the bearing for abrasion, color change, other dam-

age.

If there is any doubt as to the condition of a needle bear-

ing, replace the bearing and piston pin.

PERIODIC MAINTENANCE 2-25

Periodic Maintenance Procedures

Piston Pin Diameter

KX125

Standard: 14.995 ∼15.000 mm (0.5904 ∼ 0.5906

in.)

Service Limit: 1 4.96 mm (0.589 in.)

KX250

Standard: 17.995 ∼18.000 mm (0.7085 ∼ 0.7087

in.)

Service Limit: 1 7.96 mm (0.707 in.)

Piston Pin Hole Diameter

KX125

Standard: 15.001 ∼ 15.011 mm (0.5906 ∼ 0.5910

in.)

Service Limit: 1 5.08 mm (0.594 in.)

KX250

Standard: 18.001 ∼ 18.011 mm (0.7087 ∼ 0.7091

in.)

Service Limit: 1 8.08 mm (0.712 in.)

Small End Inside Diameter

KX125

Standard: 19.003 ∼ 19.014 mm (0.7481 ∼ 0.7486

in.)

Service Limit: 1 9.05 mm (0.750 in.)

KX250

Standard: 22.003 ∼ 22.012 mm (0.8663 ∼ 0.8666

in.)

Service Limit: 2 2.05 mm (0.868 in.)

Exhaust Valve Clean and Inspect

•

Refer to the Exhaust Valve (KIPS) section in the Engine

Top End chapter.

Exhaust System

•

The exhaust system, in particular, the baffle is equipped

in the muffler body to reduce exhaust noise and conduct

the exhaust gases away from the rider while minimizing

power loss. If carbon has built up inside the baffle, ex-

haust efficiency is reduced, causing engine performance

to drop.

•

If the muffler body is badly damaged, dented, cracked or

rusted, replace it. Replace the muffler baffle if the exhaust

noise becomes too loud or engine performance drops.

2-26 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Muffler Baffle Change

•

Remove the muffler body.

•

Remove the m uffler pipe mounting bolts [A], and pull the

muffler pipe [B] from the muffler body.

•

Unscrew the inner pipe bolts [A].

•

Pull the inner pipe [B] from the muffler body.

•

Pull off the old muffler baffle, and install the new muffler

baffle [A] into the muffler body.

•

Apply silicone sealant to the circumference [B] of the muf-

fler pipe and inner pipe.

•

Apply a non-permanent locking agent to the pipe mount-

ing bolts.

•

Tighten:

Torque - Inner Pipe Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Muffler Pipe Mounting Bolts: 8.8 N·m (0.9 kgf·m,

78 in·lb)

•

Install the muffler body and tighten the bolts.

Torque - Muffler Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Engine Right S ide

WARNING

To avoid a serious burn, never touch the hot engine

or exhaust chamber during clutch adjustment.

Clutch Lever Free Play Check

•

Slide the clutch lever dust cover [A] out of place.

•

Check that the clutch cable upper end is fully seated in

the adjuster [B].

•

Check that the clutch lever [C] has 2 ∼ 3mm(0.08∼ 0.12

in.) of play [D].

If it does not, adjust the clutch lever free play.

PERIODIC MAINTENANCE 2-27

Periodic Maintenance Procedures

Clutch Leve r Free Play Adjustment

•

Slide the clutch lever dust cover out of place.

•

Loosen the knurled locknut [A].

•

Turn the adjuster [B] so that the clutch lever will have 2 ∼

3 mm (0.08 ∼ 0.12 in.) of play [C].

NOTE

○

Be sure that the outer cable end at the clutch lever is

fully seated in the adjuster at the clutch lever, or it could

slip into the place later, creating enough cable play to

prevent clutch disengagement.

•

Tighten the locknut.

•

If it cannot be done, loosen the locknut [A] at the lower

of the c lutch cable, and turn the adjusting nut [B] so that

clutch lever has 2 ∼ 3 mm (0.08 ∼ 0.12 in.) of play.

•

After the adjustment is made, tighten the locknut, and

start the engine and check that the clutch does not slip

and that it release properly.

Friction and Steel Plates Wear, Damage Inspection

•

Visually inspect the friction and steel plates to see if they

show any signs of seizure, or uneven wear.

If any plates show signs of damage, replace the friction

plates and steel plates as a set.

•

Measure the thickness [A] of the friction plates [B] and

steel plates with vernier calipers.

If they have worn past the service limit, replace them with

new ones.

Friction Plate Thickness

KX125:

Standard: 2.72 ∼ 2.88 mm (0.107 ∼ 0.113 in.)

Service Limit: 2.6 mm (0.102 in.)

KX250:

Standard: 2.92 ∼ 3.08 mm (0.115 ∼ 0.121 in.)

Service L imit: 2.8 mm (0.110 in.)

Steel Plate Thickness

KX125:

Standard: 1.5 ∼ 1.7 mm (0.059 ∼ 0.067 in.)

Service Limit: 1.4 mm (0.055 in.)

KX250:

Standard: 1.46 ∼ 1.74 mm (0.057 ∼ 0.069 in.)

Service L imit: 1.36 mm (0.05 4 in.)

2-28 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Friction and Steel Plate Warp Inspection

•

Place each friction plate or steel plate on a surface plate,

and measure the gap between the surface plate [A] and

each friction plate or steel plate [B] with a thickness gauge

[C]. The gap is the amount of friction or steel plate warp.

If any plate is warped over the service limit, replace it with

a new one.

Friction and Steel Plates Warp

Standard:

Friction Plate 0.15 mm (0.006 in.) or less

Steel Plate 0.2 mm (0.008 in.) or less

Service Limit:

Friction Plate 0.3 mm (0.012 in.)

Steel Plate 0.3 mm (0.012 in.)

Engine Bottom End/Transmission

In order for the transmission and clutch to function prop-

erly, always maintain the transmission oil at the proper level

and change the oil periodically.

WARNING

Motorcycle operation with insufficient, deteri-

orated, or contaminated transmission oil will

accelerated wear and may result in transmission

seizure, and injury.

Transmission Oil Level Inspection

•

Situate the motorcycle so that it is perpendicular to the

ground.

•

If the motorcycle has just been used, wait several minutes

until the oil settles.

•

Check that the oil level comes up between the upper level

[A] and lower level [B] through the oil level gauge [C] on

the clutch cover.

If the oil level is too high, remove the excess oil through

the oil filler opening using a syringe or some other suitable

device.

If the o il level is too low, add the correct amount of oil.

Use the same type and make of oil that is already in the

engine.

NOTE

○

If the transmission oil type and make are unknown, use

any brand of the specified oil to top up the level in pref-

erence to running the engine with the oil level low. Then

at your earliest convenience, change the oil completely.

PERIODIC MAINTENANCE 2-29

Periodic Maintenance Procedures

Transmission Oil Change

•

Warm up the engine thoroughly so that the oil will pick up

any sediment and drain easily. Then stop the engine.

•

Place an oil pan beneath the engine.

•

Remove the engine oil drain plug [A] on the bottom of the

engine, and let the oil d rain completely.

NOTE

○

Hold the motorcycle upright so that the oil may drain

completely.

•

Replace the gasket at the drain plug with a new one.

•

After the oil has completely drained out, install the drain

plug with the gasket, and tighten it.

Torque - Engine Oil Drain Plug: 20 N·m (2.0 kgf·m, 14.5 ft·lb)

•

Fill the transmission with a good quality engine oil speci-

fied below.

•

Check the oil level.

Recommended Transmission Oil

Grade API SE, SF or SG

API SH, SJ or SL with JASO MA

Viscosity

SAE10W-40

Capacity KX125: 0.7 L (0.74 US qt.)

KX250: 0.85 L (0.90 US qt.)

NOTE

○

Although 10W-40 engine oil is the recommended oil

for most conditions, the oil viscosity may need to be

changed to accommodate atmospheric conditions in

your riding area.

Wheel/Ti res

Air Pressure Inspection/Adjustment

•

Using tire air pressure gauge [A], measure the tire pres-

sure when the tires are cold.

Adjust the tire air pressure to suit track conditions and

rider preference, but do not stray too far from the recom-

mended pressure.

Track Condition

Tire Pressure

When the track is wet, muddy, sandy

or slippery, reduce the tire pressure

to increase the tire tread surface on

the ground.

80kPa(0.8kgf/cm²,

11 psi)

↑

When the track is pebbly or hard,

increasethetirepressuretoprevent

damage or punctures, though the

tires w ill skid more easily.

↓

100 kPa (1.0 kgf/cm ²,

14 psi)

2-30 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Tires Inspection

As the tire tread wears down, the tire becomes more sus-

ceptible the puncture and failure.

•

Remove any imbedded stones or other foreign particles

from the tread.

•

Visually inspect the tire for cracks and cuts, replacing the

tire in case of bad damage. Swelling or high spots indi-

cate internal damage, requiring tire replacement.

WARNING

To ensure safe handling and stability, use only the

recommended standard tires for replacement, in-

flated to the standard pressure.

NOTE

○

Check and balance the wheel when a tire is replaced

with a new one.

Standard Tire

KX125

Front:

Size: 80/100-21 51M

Make:

DUNLOP

Type:

(KX125-M1 ∼ M2) D739FA, Tube (EUR) D755FJ,

Tube

(KX125-M3 ∼) D742F, Tube (EUR) D755FJ,

Tube

Rear:

Size: 100/90-19 57M

Make:

DUNLOP

Type:

(KX125-M1 ∼ M2) D739, Tube (EUR) D755G, Tube

(KX125-M3 ∼) D756, Tube (EUR) D755G, Tube

KX250:

Front:

Size: 80/100-21 51M

Make:

BRIDGESTONE (EUR) DUNLOP

Type:

M601, Tube (EUR) D755FJ, Tube

Rear:

Size: 110/90-19 62M

Make:

BRIDGESTONE (EUR) DUNLOP

Type:

M602, Tube (EUR) D755J, Tube

EUR: Europe Model

PERIODIC MAINTENANCE 2-31

Periodic Maintenance Procedures

Spoke Tightness Inspection

•

Check that all the s pokes are tightened evenly.

If spoke tightness is uneven or loose, tighten the spoke

nipples evenly.

Torque - Spoke Nipples: 2.2 N·m (0.22 kgf·m, 19 in·lb)

•

Check the rim runout.

WARNING

If any spoke breaks, it should be replaced immedi-

ately. A missing spoke places an additional load on

the other spokes, which will eventually cause other

spokes to break.

Rim Runout Inspection

•

Place the jack under the frame so that the front/rear wheel

off the ground.

Special Tool - Jack: 57001-1238

•

Inspect the rim for small cracks, dents, bending, or warp-

ing.

If there is any damage to the rim, it must be replaced.

•

Set a dial gauge against the side of the rim, and rotate

the rim to measure the axial runout [A]. The difference be-

tween the highest and lowest dial readings is the amount

of runout.

•

Set a dial gauge against the outer circumference of the

rim, and rotate the rim to measure radial runout [B]. The

difference between the highest and lowest dial readings

is the amount of runout.

If rim runout exceeds the service limit, check the wheel

bearings first. Replace them if they are damaged. If the

problem is not due to the bearings, correct the rim warp

(runout). A certain amount of rim warp can be corrected

by recentering the rim. Loosen some spokes and tighten

others within the standard torque to change the position of

different parts of the rim. If the rim is badly bent, however,

it must be replaced.

Rim Runout (with tire installed)

Standard:

Axial 1.0 mm (0.04 i n.) or l ess

Radial 1.0 mm (0.04 in.) or less

Service Limit:

Axial 2 mm (0.08 in.)

Radial 2 mm (0.08 in.)

Wheel Bearing Inspection

•

Refer to the Hub Bearing Inspection in the Wheels/Ti res

chapter.

2-32 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Final Drive

Drive Chain Slack Inspection

•

Raise the rear wheel off the ground, rotate the rear wheel

to find the place where the chain is tightest (because it

wears unevenly).

•

Check the wheel alignment (see Wheel Alignment Inspec-

tion in the Final Drive chapter), and adjust it if necessary

(see Wheel Alignment Adjustment in the Final Drive c hap-

ter).

NOTE

○

Clean the drive chain if it is dirty, and lubricate it if it

appears dry.

•

Rotate the rear wheel to find the position where the chain

is tightest.

•

Measure the space (chain slack) [A] between the chain

and the swing-arm at the rear of the chain slipper as

shown.

If the drive chain slack exceeds the standard, adjust it.

Chain Slack

Standard: 52 ∼ 62 mm (2.05 ∼ 2.44 in.)

Drive Chain Slack Adjustment

•

Loosen the left and right chain adjuster locknuts [A].

•

Remove the cotter pin [B] and loosen the axle nut [C].

If the chain is too tight, back out the left and right chain

adjusting bolts [D] evenly, and push the wheel forward

until the chain is too loose.

If the chain is too loose, turn both chain adjusting bolts

evenly until the drive chain has the c orrect amount of

slack. To keep the chain and wheel properly aligned, the

rear end of the left chain adjuster should align with the

same swingarm mark [E] as the right chain adjuster rear

end [F].

•

Check the wheel alignment.

•

Tighten both chain adjuster locknuts securely.

•

Tighten the axle nut.

Torque - Rear Axle Nut: 108 N·m (11.0 kgf·m, 80 ft·lb)

•

Rotate the wheel, measure the chain slack again at the

tightest position, and readjust if necessary.

•

Install a new cotter pin [A] through the axle nut and axle,

and spread its ends.

PERIODIC MAINTENANCE 2-33

Periodic Maintenance Procedures

NOTE

○

When inserting the cotter pin, if the slots in the nut do

not align with the cotter pin hole in the axle shaft, tighten

the nut clockwise [A] up to next alignment.

○

It should be within 30 degree.

○

Loosen once tighten again when the s lot goes past the

nearest hole.

WARNING

If the axle nut is not securely tightened, or the cotter

pin is not installed, an unsafe riding condition may

result.

•

Check the rear brake (see Brakes chapter).

NOTE

○

In wet and muddy conditions, mud sticks to the chain

and sprockets resulting in an overly tight chain, and the

chain may break. To prevent this, adjust the chain to 62

∼

72 mm (2.44

∼

2.83 in.) of slack whenever necessary.

Drive Chain Wear Inspection

•

Rotate the rear wheel to inspect the drive chain for dam-

aged rollers, and loose pins and links.

If there is any irregularity, replace the drive chain.

Lubricate the drive chain if it appears dry.

A. Bushing

B. Roller

C. Pin

D. Pin Link

E. Roller Link

•

Stretch the chain taut by hanging a 98 N (10 kgf, 20 lb)

weight [A] on the chain.

•

Measure the length of 20 links [B] on the straight part [C] of

the chain from the pin c enter of the 1st pin to the pin center

of the 21st pin. Since the chain may wear unevenly, take

measurements at several places.

Chain 20-link Length

Standard: 317.5 ∼ 318.2 mm (12.50 ∼ 12.53 in.)

Service Limit: 323 m m (12.72 in.)

If any measurements exceed the service limit, replace the

chain. Also, replace the front and rear sprockets when the

drive chain is replaced.

2-34 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

WARNING

If the drive chain wear exceeds the service limit, re-

place the chain or an unsafe r iding condition may

result. A chain that breaks or jumps off the sprock-

ets could snag on the engine sprocket or lock the

rear wheel, severely damaging the m otorcycle and

causing it to go out of control.

Standard Chain

Make:

DAIDO

Ty pe: D.I.D 520DMA2

Link:

KX125-M1 112 Links

KX125-M2 ∼ 114 Links

KX250 114 Links

Drive Chain Lubrication

•

If the chain appears especially dirty, it should be cleaned

before lubrication with high flash-point solvent.

•

If a special lubricant is not available, a heavy oil such as

SAE90 is preferred to a lighter oil because it will stay on

the chain longer and provide better lubrication.

•

Apply oil to the sides of the rollers so that oil will penetrate

to the rollers and bushings.

•

Wipe off any excess oil.

Oil applied area [A]

Sprocket Wear Inspection

•

Visually inspect the front and rear sprocket teeth for wear

and damage.

If they are worn as illustrated or damaged, replace the

sprocket.

A. Worn Tooth (Engine Sprocket)

B. Worn Tooth (Rear Sprocket)

C. Direction of Rotation

NOTE

○

If a sprocket requires replacement, the chain is proba-

bly worn also. When replacing a sprocket, inspect the

chain.

PERIODIC MAINTENANCE 2-35

Periodic Maintenance Procedures

Rear Sprocket Warp Inspection

•

Using the jack, raise the rear wheel off the ground.

Special Tool - Jack: 57001-1238

•

Set a dial gauge [A] against the rear sprocket [B] near the

teeth as shown and rotate [C] the rear wheel to measure

the sprocket runout (warp). The difference between the

highest and lowest dial gauge readings is the amount of

runout (warp).

If the runout exceeds the service limit, replace the rear

sprocket.

Rear Sprocket Warp

Standard: 0.4 mm (0.016 in.) or less

Service Limit: 0.5 m m (0.020 in.)

Brakes

Brake Lever Play Adjustment

•

Adjust the front brake lever [A] to suit you.

•

Slide the brake lever dust cover [B] out of place.

•

Loosen the adjuster locknut [C] and turn the adjuster [D]

to either side.

•

After adjustment, tighten the locknut.

WARNING

Always maintain proper brake adjustment. If ad-

justment is improper, the brake could drag and

overheat. This could damage the brake assembly

and possibly lock the wheel resulting in loss of

control.

2-36 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Brake Fluid Level Inspection

In accordance with the Periodic Maintenance Chart, in-

spect the brake fluid level in the front or rear brake fluid

reservoirs.

•

Check the brake fluid level in the front or rear brake reser-

voir [A].

NOTE

○

Hold the reservoir horizontal when checking brake fluid

level.

○

The front or rear reservoir must be kept above the lower

level line [B]. If the fluid level in front or rear reservoir is

lower than the lower level line, fill the reservoir to the

upper level line. Inside the reservoir is stopped end

showing the upper level line [C].

PERIODIC MAINTENANCE 2-37

Periodic Maintenance Procedures

Brake Fluid Change

In accordance with the Periodic Maintenance Chart,

change the brake fluid. The brake fluid should also be

changed if it becomes contaminated with dirt or water.

Furthermore, the brake fluid should be changed to bleed

the air quickly and completely whenever the brake line

parts are removed.

WARNING

Change the brake fluid in the brake line completely

if the brake fluid must be refilled but the type and

brand of the brake fluid that already is in the reser-

voir are unidentified. After changing the fluid, use

only the same type and brand of fluid thereafter.

Mixing different types and brand o f brake fluid low-

ers the brake fluid boiling point and could cause the

brake to be ineffective. It may also cause the rubber

brake parts to deteriorate.

Recommended Disc Brake Fluid

Type:

Front

DOT3 or DOT4

Rear

DOT4

NOTE

○

The procedure to change the front brake fluid. Chang-

ing the rear brake fluid is the same as for the front brake.

•

Level the brake fluid reservoir.

•

Remove the reservoir cap.

•

Remove the rubber cap [A] on the bleed valve [B].

•

Attach a clear plastic hose to the bleed valve on the

caliper, and run the other end of the hose into a con-

tainer.

•

For KX125/250-M2 model∼; as shown in the figure.

2-38 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

•

Change the brake fluid as follows:

○

Repeat this operation until fresh brake fluid comes out

from the plastic hose or the color of the fluid changes.

1. Open the bleed valve [A]

2. Apply the brake and hold it [B]

3. Close the bleed valve [C]

4. Release the brake [D]

○

Fill the reservoir with fresh specified brake fluid.

NOTE

○

The fluid level must be checked often during the chang-

ing operation and replenished with fresh brake fluid. If

the fluid in the reservoir runs out any time during the

changing operation, the brakes will need to be bled

since air will have entered the brake line.

•

Remove the clear plastic hose.

•

Tighten the bleed valves, and install the rubber caps.

Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)

•

After c hanging the fluid, check the brake for good braking

power, no brake drag, and no fluid leakage.

If necessary, bleed the air from the lines.

WARNING

Do not mix two brands of fluid. Change the brake

fluid in the brake line completely if the brake fluid

must be refilled but the type and brand of the brake

fluid that is already in the reservoir are unidentified.

Brake Pad Wear Inspection

•

Remove the brake pad (see Brake Pad Removal in

Brakes chapter).

•

Check the lining thickness and condition of the pads in

each caliper.

If either pad is damaged, replace both pads in the c aliper

as a set.

If the lining thickness [A] of either pad is less than the

service limit [B], replace both pads in the caliper as a set.

Lining Thickness

Standard:

Front

3.8 mm (0.150 in.)

Rear

6.4 mm (0.252 in.)

Service Limit:

Front

1 mm ( 0.04 in.)

Rear

1 mm ( 0.04 in.)

•

Install the brake pad (see Brake Pad Installation in Brakes

chapter).

•

Tighten:

Torque - Brake Pad Bolt: 18 N·m (1.8 kgf·m, 13 ft·lb)

Brake Master Cylinder Cup and Dust Seal

Replacement

•

Refer to the Master Cylinder section in the Brakes chapter

for Brake Master Cylinder Seal Replacement.

PERIODIC MAINTENANCE 2-39

Periodic Maintenance Procedures

Caliper Fluid Seal and Dust Seal Replacement

•

Refer to the Calipers section in the Brakes chapter for

Caliper Fluid and Dust Seal Damage.

Brake Hose and Conne ction Check

•

Inspect the brake hose and fittings for deterioration,

cracks and signs of leakage.

○

The high pressure inside the brake line can cause fluid to

leak [A] or the hose to burst if the line is not properly main-

tained. Bend and twist the rubber hose while examining

it.

Replace the hose if any cracks [B] or bulges [C] are no-

ticed.

Tighten any loose fittings.

Suspension

Front Fork O il Leak Inspection

•

Visually inspect the front fork for oil leakage, scoring or

scratches on the outer surface of the inner tube [A].

If necessary, repair any damage.

•

Nick or rust damage can sometimes be repaired by using

a wet-stone to remove sharp edges or raised areas which

cause seal damage.

If the damage is not repairable, replace the inner tube.

Since damage to the inner tube damages the oil seal,

replace the oil seal whenever the i nner tube is repaired

or replaced.

•

Temporarily assemble the inner and outer tubes, and

pump them back and forth manually to check for smooth

operation.

CAUTION

If the inner tube is badly bent or creased, replace

it. Excessive bending, followed by subsequent

straightening, can weaken the inner tube.

•

For KX125/250-M2 model ∼; as shown in the figure.

2-40 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

Front Fork Oil Cha nge/Oil Level Adjustment (each

fork leg)

•

Loosen the front fork upper clamp bolts.

•

Place the handlebar on one side, and loosen the fork top

plug.

•

Remove the front fork.

•

Hold the inner tube lower end in a vise.

•

Disassemble the top plug from the outer tube.

•

Push the outer tube all the way down away from the top

plug and hold it there throughout the following procedure.

○

For KX125/250-M1 model, pull the fork spring [A] away

from the top plug a little and slip the spanner wrench [B]

in on top of the spring seat and under the push rod nut

[C].

•

Use wrenches on the rod nut and the top plug [A] to loosen

the push rod nut.

•

Remove the top plug from the push rod.

•

Lift the fork spring [B] and its top spring seat [C] out of the

outer tube.

•

For KX125/250-M2 model ∼; as shown in the figure.

•

Take the rebound damping adjuster rod [A] out of the push

rod.

PERIODIC MAINTENANCE 2-41

Periodic Maintenance Procedures

•

Hold the fork tube [A] upside down over a clean container

[B] and pump it to drain the oil.

NOTE

○

To discharge the fork oil, pump the push rod up [C] and

down ten times.

•

Hold the fork tube upright, press the outer tube and the

push rod all the way down.

•

Insert the rebound damping adjuster rod into the push rod.

NOTE

○

The spring should not be installed.

•

Fill the specified oil to the outer tube.

Recommended Oil

KHL15-10 (KAYABA 01) or equivalent

Front Fork Oil Capacity

KX125-M1:

652 ±4 mL (22.04 ±0.14 US oz)

KX125-M2∼:

565 ±4 mL (19.10 ±0.14 US oz)

KX250-M1:

664 ±4 mL (22.45 ±0.14 US oz)

KX250-M2∼:

578 ±4 mL (19.54 ±0.14 US oz)

NOTE

○

While doing this, take care to keep the oil level topped

off so that it stays above the two large holes [A] near

the top of the inner tube [B].

•

Screw the fork piston rod puller [A] onto the end of the

push rod.

Special Tool - Fork Piston Rod Puller, M12 x 1.25: 57001

-1289

•

Purge the air from the fork cylinder by gently moving the

piston rod puller up and down five times.

•

Remove the fork piston rod puller.

2-42 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

•

Purge the air from between the inner and outer tubes by

pumping the outer tube [A] up and down.

•

After purging the air from the assembly, let it sit for about

five minutes so that any suspended air bubbles can sur-

face.

•

Install the spring guide.

•

Screw the push rod nut.

•

Adjust the oil level.

○

With the fork fully compressed, put the oil level gauge [A]

and the stopper [B], and inspect the distance from the top

of the inner tube to the oil.

Special Tool - Fork Oil Level Gauge: 57001-1290

Oil Level (fully compressed, without spring)

Standard

KX125-M1: 133 ∼ 137 mm (5.24 ∼ 5.39 in.)

KX125-M2∼:103∼ 107 mm (4.06 ∼ 4.21 in.)

KX250-M1: 123 ∼ 127 mm (4.84 ∼ 5.00 in.)

KX250-M2∼:86∼ 90 mm (3.39 ∼ 3.54 in.)

Adjustable Range

KX125/250-M1: 100 ∼ 145 mm (3.94 ∼ 5.71 in.)

KX125/250-M2∼:70∼ 120 mm (2.76 ∼ 4.72 in.)

If no oil is drawn out, there is insufficient oil in the outer

tube. Pour in enough oil, then drawn out the excess oil.

•

Install the parts removed (see Front Fork Assembly in

Suspension chapter).

Rear Shock Absorber Oil Change

•

Refer to the Rear Suspension (Uni-Trak) section in the

Suspension chapter for Rear Shock Absorber Disassem-

bly (Oil Change) and Assembly.

Uni-Trak Linkage Inspection

•

Check the uni-trak component parts for wear periodically,

or whenever excessive play is suspected.

•

Using the jack under the frame, raise the rear wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Push and pull on the swingarm [A], up and down, to check

for wear.

A small amount of play on the swingarm is normal and no

corrective action is needed. However, if excessive play is

felt, remove the uni-trak parts from the frame and check

for wear.

PERIODIC MAINTENANCE 2-43

Periodic Maintenance Procedures

Chain Guide Wear Inspection

•

Visually inspect the drive chain guide [A] and replace it if

excessively worn or damaged.

Chain Slipper Wear Inspectio n

•

Visually inspect the upper and lower chain slippers [A] on

the swingarm [B] and replace them if worn or damaged.

Steering

Steering Inspection

•

Using the jack, raise the front wheel off the ground.

Special Tool - Jack: 57001-1238

•

With the front wheel pointing straight ahead, alternately

nudge each end of the handlebar. The front wheel should

swing fully left and right from the force of gravity until the

fork hits the stop.

If the steering binds or catches before the stop, check the

routing of the cables, hoses, and harnesses.

If the steering feels tight, adjust or lubricate the steering.

•

Feel for steering looseness by pushing and pulling the

forks.

If you feel looseness, adjust the steering.

•

For KX125/250-M2 model ∼; as shown in the figure.

Steering Adjustment

•

Using the jack, raise the front wheel off the ground.

Special Tool - Jack: 57001-1238

2-44 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

KX125-M1 ∼ M3/KX250-M1 ∼ M2;

•

Slide the holder belt [A] out off.

•

Remove number plate bolt [B] and number plate [C].

•

Remove:

Handlebar Clamp Bolts [A]

Handlebar Clamp [B]

Handle Bar [C]

KX125M6F ∼;

•

Remove:

Number Plate [A]

Pad [B]

•

Remove:

Handlebar Clamp Bolts [A]

Handlebar Clamps [B]

Handlebar [C]

•

Loosen the front fork upper clamp bolts [A], and remove

the steering stem head nut [B] and steering stem head

[C].

PERIODIC MAINTENANCE 2-45

Periodic Maintenance Procedures

•

Turn the steering stem locknut [A] with the steering s tem

nut wrench [B] to obtain the proper adjustment.

If the steering is too tight, loosen the stem locknut a frac-

tion of a turn; if the steering is too loose, tighten the lock-

nut a fraction of a turn.

Special Tool - Steering Stem N ut Wrench: 57001-1100

NOTE

○

Turn the locknut 1/8 turn at a time maximum.

•

Install the steering stem head.

•

Tighten the following:

Torque - Steering Stem Head Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

Front Fork Clamp Bolts: (Upper): 20 N·m (2.0

kgf·m , 14.5 ft·lb)

NOTE

○

Tighten the two clamp bolts alternately two times to en-

sure even tightening torque.

•

Check the steering again.

If the steering is too tight or too loose, repeat the adjust-

ment as mentioned above.

KX125-M1 ∼ M3/KX250-M1 ∼ M2;

•

Install the handlebar [A] on the handlebar holder as

shown.

Same Length [B]

Bridge Bar [C]

•

Install the handlebar clamp [A] together with the handle-

bar so that the cut side [B] on the clamp points at the front.

•

Tighten the handlebar clamp bolts [C].

Torque - Handlebar Clamp Bolts: 25 N·m (2.5 kgf·m, 18

ft·lb)

○

Tighten the clamp bolts, rear first and then the front. If

the handlebar clamp is correctly installed, there will be no

gap at the rear and a gap at the front after tightening.

•

Install the number plate.

2-46 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

KX125M6F ∼;

•

Install the handlebar [A] on the handlebar holder as

shown.

Same Length [B]

Bridge Bar [C]

Protrusion of Graduation [D]

•

Install the handlebar clamps. [A] with handlebar.

○

Tighten the front and rear bolts [B] of the handlebar

clamps equally.

Torque - Handlebar Clamp Bolts: 25 N·m (2.5 kgf·m, 18

ft·lb)

If the handlebar clamps are correctly installed, there will

be same amount of gap [C] on the front and rear side of

the clamp after the bolts tightening.

•

Install:

Pad

Number Plate

Stem Bearing Lubrication

•

Remove the steering stem (see Steering Stem Removal

in Steering chapter).

•

Using a high-flash point solvent, wash the upper and

lower tapered rollers in the cages, and wipe the upper

and lower outer races, which are press-fitted into the

frame head pipe, clean off grease and dirt.

•

Visually check the outer races and the rollers.

Replace the bearing assemblies if they show wear or

damage.

•

Pack the upper and lower tapered roller bearings [A] in

the cages with grease, and apply a light coat of grease to

the upper and lower outer races.

•

Install the steering stem, and adjust the steering (see

Steering Stem, Stem Bearing Installation, Steering Ad-

justment in Steering chapter).

Frame

Frame Inspection

•

Clean the frame with steam cleaner.

•

Visually inspect the frame and rear frame for cracks,

dents, bending, or warp.

If there is a ny damage to the frame, replace it.

WARNING

A repaired frame may fail in use, possibly causing

an accident. If the frame is bent, dented, cracked,

or warped, replace it.

PERIODIC MAINTENANCE 2-47

Periodic Maintenance Procedures

Electrical System

Spark Plug Cleaning and Inspection

•

Remove the spark plug, and visually inspect it.

•

Clean the spark plug, preferably in a sandblasting device,

and then clean off any abrasive particles. The plug may

also be cleaned using a high-flash point solvent and a wire

brush or other suitable tool.

If the spark plug electrodes are corroded or damaged,

or if the insulator is cracked, replace the plug. Use the

standard spark plug.

Spark Plug G ap Inspection

•

Measure the gap [A] with a wire-type thickness gauge.

If the gap is incorrect, carefully bend the side electrode

[B] with a suitable tool to obtain the correct gap.

Spark Plug Gap

Standard 0.7 ∼ 0.8 mm (0.028 ∼ 0.031 in.)

2-48 PERIODIC MAINTENANCE

Periodic Maintenance Procedures

General Lubrication

Lubrication

•

Before lubricating each part, clean off any rusty spots with

rust remover and wipe off any grease, oil, dirt, or grime.

•

Lubricate the points listed below with indicated lubricant.

NOTE

○

Whenever the vehicle has been operated under

wet or rainy conditions, or especially after using a

high-pressure water spray, perform the general lubri-

cation.

Pivots: Lubricate with Engine Oil

Clutch Lever

Brake Lever

Kick Pedal

Shift Pedal

Rear Brake Rod Joint

Drive Chain

Points: Lubricate with Grease.

Clutch Inner Cable Upper and Lower Ends [A]

Throttle Inner Cable Upper End

Swingarm Pivot

Tie-Rod Pivot

Rocker Arm Pivot

Steering Stem Bearing

Cables: Lubricate with Rust Inhibitor.

Throttle Cable

Clutch Cable

•

With the cable disconnected at the both ends, the cable

should move freely [A] within the cable housing.

If cable movement is not free after lubricating, if the c able

is frayed [B], or if the cable housing is kinked [C], replace

the cable.

PERIODIC MAINTENANCE 2-49

Periodic Maintenance Procedures

Nut, Bolt, and Fastener Tightness

Tightness Inspection

•

Check the tightness of bolts and nuts listed here. Also,

check to s ee that each cotter pin is in place and in good

condition.

NOTE

○

For the engine fasteners, check the tightness of them

when the engine is cold (at room temperature).

If there are loose fasteners, retorque them to the spec-

ified torque following the specified tightening sequence.

Refer to the appropriate chapter for torque specifications.

If torque specifications are not in the appropriate chapter,

see the Standard Torque Table. For each fastener, first

loosen it by 1/2 turn, then tighten it.

If cotter pins are damaged, replace them with new ones.

Nut, Bolt and Fastener to be checked

Wheels:

Spoke N ipples

Front Axle Nut

Rear Axle Nut Cotter P in

Rear Axle Nut

Final Drive:

Chain Adjuster Locknuts

Rear Sprocket Nuts

Brakes:

Front Master Cylinder Clamp Bolts

Caliper Mounting Bolts (Front)

Rear Master Cylinder Mounting Bolts

Rear Master Cylinder Joint Cotter Pin

Brake Lever Pivot Nut

Brake Pedal Mounting Bolt

Suspension:

Front Fork Clamp Bolts

Front Fender Mounting Bolt

Rear Shock Absorber Mounting Nuts

Swingarm Pivot Shaft Nut

Uni-Trak Link Nuts

Steering:

Steering Stem H ead Nut

Handlebar Clamp Bolts

Engine:

Engine Mounting Nuts

Engine Bracket Nuts

Cylinder Head Nuts

Shift Pedal Bolt

Muffler Bolt and Nut

Kick Pedal Bolt

Others:

Rear Frame Mounting Bolts

FUEL SYSTEM 3-1

Fuel System

Table of Contents

Exploded View........................................................................................................................ 3-2

Specifications ......................................................................................................................... 3-8

Special Tools .......................................................................................................................... 3-9

Throttle Grip and Cable .......................................................................................................... 3-10

Free Play Inspection ......................................................................................................... 3-10

Free Play Adjustment ........................................................................................................ 3-10

Throttle Cable Installation ................................................................................................. 3-10

Cable Lubrication .............................................................................................................. 3-10

Cable Inspection ............................................................................................................... 3-10

Carburetor .............................................................................................................................. 3-11

Idle Speed Inspection ....................................................................................................... 3-11

Idle Speed Adjustment...................................................................................................... 3-11

Service Fuel Level Inspection ........................................................................................... 3-11

Service Fuel Level Adjustment ......................................................................................... 3-12

Carburetor Removal.......................................................................................................... 3-13

Carburetor Installation....................................................................................................... 3-14

Fuel Inspection..................................................................................................................3-15

Carburetor Disassembly ................................................................................................... 3-15

Carburetor Assembly ........................................................................................................ 3-18

Carburetor Cleaning.......................................................................................................... 3-18

Carburetor Inspection ....................................................................................................... 3-19

Air Cleaner.............................................................................................................................. 3-21

Housing Removal.............................................................................................................. 3-21

Air Cleaner Housing Installation........................................................................................ 3-21

Element Removal .............................................................................................................. 3-21

Element Installation ........................................................................................................... 3-21

Element Cleaning and Inspection ..................................................................................... 3-22

Fuel Tank................................................................................................................................ 3-23

Fuel Tank Removal ........................................................................................................... 3-23

Fuel Tank Installation ........................................................................................................ 3-23

Fuel Tap Removal ............................................................................................................. 3-23

Fuel Tap Installation .......................................................................................................... 3-23

Fuel Tap Inspection........................................................................................................... 3-23

Fuel Tank and Tap Cleaning ............................................................................................. 3-23

Reed Valve ............................................................................................................................. 3-24

Reed Valve Removal ........................................................................................................ 3-24

Reed Valve Installation ..................................................................................................... 3-24

Reed Valve Inspection ...................................................................................................... 3-24

3-2 FUEL SYSTEM

Exploded View

KX125M:

FUEL SYSTEM 3-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Carburetor Holder Mounting Bolts 8.8 0.9 78 in·lb

2 Carburetor Holding Clamp Screw 1.5 0.15 13 in·lb

3 Reed Valve Screws 1.0 0.1 8.8 in·lb

Carburetor Top Cover Screws

3.0 0.3 26 in·lb

5. Throttle Cable

6. Throttle Grip

7. Spring

8. Retainer

9. Connector

10. Jet Needle Clip

11. Jet Needle

12. Throttle Valve

13. Choke Knob

14. Idle Adjusting Screw

15. Air Screw

16. Slow Jet

17. Main Jet

18. Needle Jet

19. Main Jet Holder

20. Float Valve Needle

21. Float

22. Carburetor Holder

23a. Reed Valve (KX125-M1 Model)

23b. Reed Valve (KX125-M2 Model∼)

G: Apply grease.

O: Apply oil.

3-4 FUEL SYSTEM

Exploded View

KX250M:

FUEL SYSTEM 3-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Carburetor Holder Mounting Bolts 8.8 0.9 78 in·lb

2 Carburetor Holding Clamp Screw 1.5 0.15 13 in·lb

3 Reed Valve Screws 1.0 0.1 8.8 in·lb

Throttle Sensor Bolt

2.0 0.2 17 in·lb

5 Carburetor Top Cover Allen Bolts 3.9 0.4 35 in·lb

6. Throttle Cable

7. Throttle Grip

8. Spring

9. Retainer

10. Connector

11. Jet Needle Clip

12. Jet Needle

13. Throttle Valve

14. Choke Knob

15. Idle Adjusting Screw

16. Spring

17. Air Screw

18. Slow Jet

19. Power Jet

20. Main Jet

21. Float Valve Needle

22. Float

23. Throttle Sensor

24. Fuel Cut Valve

25. Carburetor Holder

26. Reed Valve

G: Apply grease.

O: Apply oil.

3-6 FUEL SYSTEM

Exploded View

FUEL SYSTEM 3-7

Exploded View

Torque

No Fastener

N·m kgf·m ft·lb

Remarks

1 Rear Frame Mounting Bolts 34 3.5 25

2 Air Cleaner Duct Clamp Screw 1.5 0.15 13 in·lb

3 Fuel Tap Plate Mounting Screws 0.8 0.08 7in·lb

4 Air Cleaner Duct Nuts 3.0 0.3 26 in·lb

5 Air Cleaner Housing Bolts 8.8 0.9 78 in·lb

6. Fuel Tank Cap

7. Fuel Tank

8. Fuel Tap

9. Element

10. Frame

11. Holder

12. Air Cleaner Duct

13. Air Cleaner Housing

14. Rear Frame

G: Apply grease.

O: High-quality foam-air-filter oil.

3-8 FUEL SYSTEM

Specifications

KX125:

Standard

Item

KX125-M1 KX125-M2 KX125-M3 ∼

Service Limit

Carburetor

Make/Type

MIKUNI TMX38χ –––

Main Jet: #420 –––

Throttle Valve Cutaway #5.75 –––

Jet Needle 6CHJ 11-82 6CHJ 10-82 –––

Jet Needle Clip Position 3rd groove from the top –––

Slow Jet (Pilot Jet) #40 –––

Air Screw (Turns out) 21/2 11/2

–––

Service Fuel Level 10 ±1 mm (0.394 ±0.039 in.) –––

(above the bottom edge

of the carb. body)

Float Height 9.5 ±1 mm (0.374 ±0.039 in.) –––

KX250:

Standard

tem

KX250-M1 KX250-M2

Service Limit

Carburetor

Make/Type KEIHIN PWK38S –––

Main Jet: #165 –––

Power Jet: #50

Throttle Valve Cutaway #8 –––

Jet Needle NAFH NALF –––

Jet Needle Clip Position 2nd groove from the top

Slow Jet (Pilot Jet) #52 –––

Air Screw (Turns out)

11/2

–––

Service Fuel Level 10.5 ±1 mm (0.413 ±0.039 in.)

–––

(above the bottom edge

of the carb. body)

Float Height

6.5 ±1 mm (0.256 ±0.039 in.)

–––

Fuel Cut Valve see Electrical System c hapter

Throttle Sensor see Electrical System chapter

FUEL SYSTEM 3-9

Special Tools

Fuel Level Gauge, M18 × 1.0:

57001-122

Fuel Level Gauge:

57001-1577

3-10 FUEL SYSTEM

Throttle Grip and Cable

If the throttle grip has excessive free play due to cable

stretch or misadjustment, there will be a delay in throttle re-

sponse. Also, the throttle valve may not open fully at full

throttle. On the other hand, if the throttle grip has no play,

the throttle will be hard to control, and the idle speed will

be erratic. Check the throttle grip play periodically in accor-

dance with the Periodic Maintenance Chart, and adjust the

play if necessary.

The throttle cable routing is shown in Cable, Harness,

Hose Routing in the Appendix chapter.

Free Play Inspection

•

RefertotheThrottleGripFreePlayInspectioninthePe-

riodic Maintenance chapter.

Free Play Adjustment

•

Refer to the Throttle Grip Free Play Adjustment in the

Periodic Maintenance chapter.

Throttle Cable Installation

•

Install the throttle cable in accordance with the Cable,

Harness, Hose Routing section in the Appendix chapter.

•

After the installation, adjust each cable properly.

WARNING

Operation with an incorrectly routed or improperly

adjusted cable could result in an unsafe riding con-

dition.

Cable Lubrication

•

Whenever the throttle cable is removed or in accordance

with the Periodic Maintenance Chart, lubricate the these

cables, Refer to General Lubrication in the Periodic Main-

tenance chapter.

○

Apply a thin coating of grease to the cable upper or lower

ends.

○

Use a commercially available pressure cable lubricator to

lubricate these cables.

Cable Inspection

•

With the throttle cable disconnected at both ends, the ca-

ble should move freely [A] within the cable housing.

If cable movement is not free after lubricating, if the c able

is frayed, or if the housing is kinked, replace the cable.

FUEL SYSTEM 3-11

Carburetor

Since the carburetor regulates and mixes the fuel and air

going to the engine, there are two general types of carbure-

tor trouble: too rich a mixture (too much fuel), and too lean

a mixture (too little fuel). Such trouble can be caused by

dirt, wear, maladjustment, or improper fuel level in the float

chamber. A dirty or damaged air cleaner can also alter the

fuel to air ratio.

Idle Speed Inspection

•

Refer to the Idle Speed Inspection in the Periodic Main-

tenance chapter.

Idle Speed Adjustment

•

Refer to the Idle Speed Adjustment in the Periodic Main-

tenance chapter.

Service Fuel Level Inspection

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Turn the fuel tap to the OFF position.

•

Remove the fuel tank.

•

Remove the c arburetor, and hold it in true vertical position

on a stand. The fuel hose and carburetor cable do not

have to be removed to inspect the fuel level [A].

•

Put the fuel tank on a bench, and connect the fuel tap to

the carburetor using a suitable hose.

•

Remove the drain plug from the bottom of the float bowl,

and screw a fuel level gauge [B] into the plug hole.

Special Tools - Fuel Level Gauge: 57001-1577 (KX125)

Fuel Level Gauge, M18 × 1.0: 57001-122

(KX250)

•

Hold the gauge vertically against the side of the carbure-

tor body so that the "zero" line [C] is several millimeters

higher than the bottom edge [D] of the carburetor body.

•

Turn the fuel tap to the ON position to feed fuel to the

carburetor.

•

Wait until the fuel l evel in the gauge settles.

•

Keeping the gauge vertical, slowly lower the gauge until

the “zero” line is even w ith the bottom edge of the carbu-

retor body.

NOTE

○

Do not lower the “zero” line below the bottom edge of

the carburetor body. If the gauge is lowered and then

raised again, the fuel level measure shows somewhat

higher than the actual fuel level. If the gauge is lowered

too far, dump the fuel out of it into a suitable container

and start the procedure over again.

3-12 FUEL SYSTEM

Carburetor

•

Read the fuel level in the gauge and compare it to the

specification.

Service Fuel Level

(above the bottom edge of the carb.

body)

Standard: 10±1mm(0.394±0.039in.)(KX125)

10.5 ±1 mm (0.413 ±0.0 39 in.) (KX250 )

If the fuel level is incorrect, adjust it.

•

Turn the fuel tap to the OFF position and remove the fuel

level gauge.

•

Install the drain plug on the bottom of the float bowl.

Service Fuel Level Adjustment

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Remove the carburetor, and drain the fuel into a suitable

container.

•

Remove the float bowl.

KX125:

•

Unscrew the pivot pin screw [A] and remove the float [B].

KX250:

•

Drive out the pivot pin [A] and remove the float [B].

•

Bend the tang [A] on the float arm very slightly to change

the float height. Increasing the float height lowers the fuel

level and decreasing the float height raises the fuel level.

Float Height

Standard: 9.5 ±1 mm (0.374 ±0.039 in.) (KX125)

6.5 ±1 mm (0.256 ±0.039 in.) (KX250)

FUEL SYSTEM 3-13

Carburetor

NOTE

○

Float height [A] is the distance from the float bowl mat-

ing surface [B] of the carburetor body (with the gasket

removed) to the top of the float [C]. Measure the height

with the c arburetor upside down.

○

Do not push the needle rod [D] in during the float height

measurement.

•

Assemble the c arburetor, and recheck the fuel level.

If the fuel level cannot be adjusted by this method, the

float or the float valve is damaged.

Carburetor Removal

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Turn the fuel tap to the OFF position and pull the fuel hose

off the tap.

•

For KX250, disconnect the carburetor lead connector.

•

Loosen the clamps [A], and remove the carburetor from

the end of the air cleaner duct, and then pull it out of the

carburetor holder.

If necessary, do the following procedure.

○

Remove:

Seat

Right Side Cover

Silencer

Rear Frame Bolt [A]

○

Loosen the rear frame bolts [B], pull up the rear frame [C]

with the air cleaner housing and remove the carburetor.

3-14 FUEL SYSTEM

Carburetor

•

Drain the fuel from the float bowl by removing the drain

plug. After draining, install the drain plug securely.

•

Unscrew the carburetor cap screws (KX125) or bolts

(KX250) [A].

•

Pull out the throttle valve assembly [A].

CAUTION

If the throttle valve is not removed from the cable,

wrap it in a clean cloth to avoid damage.

•

After removing the carburetor, push a clean, lint-free towel

into the carburetor holder and the air cleaner duct to keep

dirt or other foreign material from entering.

WARNING

If dirt or dust is allowed to pass through into the

carburetor, the throttle may become stuck, possibly

causing an accident.

CAUTION

If dirt gets through into the engine, excessive en-

gine wear and possibly engine damage will occur.

Carburetor Installation

•

For KX250, lifting up the link shaft end [A] of the throttle

sensor install the throttle valve assembly.

•

Being careful not to bend or otherwise damage the jet

needle. Check to see that the throttle valve [B] goes all the

way down into the carburetor body, and slides smoothly.

•

Tighten:

Torque - Carburetor Top Cover Screws: 3.0 N·m (0.3 kgf·m,

26 in·lb) (KX125)

Carburetor Top Cover Allen Bolts: 3.9 N·m (0.4

kgf·m, 35 in·lb) (KX250)

•

When installing the carburetor into the carburetor holder,

align the center [A] of the carburetor with the groove [B]

on the holder.

•

Tighten the clamps securely.

Torque - Carburetor Holding Clamp Screw: 1.5 N·m (0.15

kgf·m, 13 in·lb)

FUEL SYSTEM 3-15

Carburetor

•

Route the air vent and overflow hoses properly (see Ap-

pendix chapter).

CAUTION

Always keep the hoses free of obstruction, and

make sure they do not get pinched by the chain or

shock absorber.

•

For KX250, connect the c arburetor lead connector.

•

After installing the carburetor, do the following.

○

Turn the fuel tap to the ON position, and check for fuel

leakage from the carburetor.

WARNING

Fuel spilled from the carburetor is hazardous.

○

Adjust the following items if necessary:

Throttle Cable

Idle Speed

Fuel Inspection

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Turn the fuel tap to the OFF position.

•

Remove the carburetor.

•

Place a suitable container beneath the carburetor.

•

Remove the drain plug [A] from the bottom of the float

bowl and check for water or dirt in the fuel.

If any water or dirt comes out, clean the carburetor, fuel

tap and fuel tank (see this chapter).

•

Install the drain plug on the float bowl, and tighten it se-

curely.

•

Install the carburetor.

Carburetor Disassembly

•

Remove the carburetor.

•

Unscrew the carburetor top cap screws (KX125) or bolts

(KX250) [A].

•

Pull out the throttle valve assembly.

3-16 FUEL SYSTEM

Carburetor

•

Remove the throttle valve assembly [A], spring [B], re-

tainer [C] and carburetor cap from the carburetor cable

lower end.

•

Disassemble the throttle valve assembly; connector [A],

jet needle with circlip [B] and throttle valve [C].

•

Remove the choke knob/starter plunger assembly [A]

from the carburetor.

(For KX250)

•

Remove the fuel cut valve [A] from the carburetor.

(For KX250)

•

Remove the throttle sensor mounting bolt [A].

•

Before removing the throttle sensor [B], mark [C] the car-

buretor body and sensor so that it can be installed later in

the same position.

FUEL SYSTEM 3-17

Carburetor

(For KX250)

•

Remove the throttle sensor link assembly screws [A].

•

Remove the link assembly [B].

KX125:

•

Remove the following parts from the carburetor body.

A. Idle Adjusting Screw

B. Nut

C. Air Screw

D. Spring

E. Slow Jet

F. Ma i n J et

G. Float Valve Needle

H. Float

I. Pin Screw

J. O-ring

K. Float Bowl

L. Needle Jet

M. Main Jet Holder

N. Float Plate

KX250:

•

Remove the following parts from the carburetor body.

A. Idle Adjusting Screw

B. Spring

C. Air Screw

D. Spring

E. Slow Jet

F. Ma i n J et

G. Float Valve Needle

H. Float

I. Pin

J. O-ring

K. Float Bowl

L. Power Jet

3-18 FUEL SYSTEM

Carburetor

Carburetor Assembly

•

Clean the disassembly parts before assembling.

•

Replace the O-rings with a new one if it is deteriorated or

damaged.

•

Turn in the air screw [A] fully but not tightly, and then back

it out the specified number of turns. (see Specifications

of this chapter)

•

For KX250, install the throttle sensor so that the marks

aligns and check it position (see Electrical System chap-

ter).

•

Tighten:

Torque - Throttle Sensor bolt: 20 N·m (0.2 kgf·m, 17 in·lb)

Carburetor Cleaning

WARNING

Clean the carburetor in a well-ventilated area, and

take care that there is no spark or flame anywhere

near the working area; this includes any appliance

with a pilot light. Because of the danger of highly

flammable liquids, do not use gasoline or low flash

-point solvent to clean the carburetor.

•

Make sure the fuel tap is in the OFF position.

•

Remove the carburetor.

•

Drain the fuel in the carburetor.

•

Disassemble the carburetor.

CAUTION

Do not use compressed air on an assembled carbu-

retor, the float may be deformed by the pressure.

Remove as many rubber or plastic parts from the

carburetor as possible before cleaning the carbu-

retor with a cleaning solution. This will prevent

damage or deterioration of the parts. Do not use

a strong carburetor cleaning solution which could

attack the plastic parts; instead, use a mild high

flash-point cleaning solution safe for plastic parts.

Do not use wire or any other hard instrument to

clean carburetor parts, especially jets, as they may

be damaged.

•

Immerse all the metal parts in a carburetor cleaning solu-

tion.

•

Rinse the parts in water.

•

After the parts are cleaned, dry them with compressed air.

•

Blow through the air and fuel passages with compressed

air.

•

Assemble the carburetor, and install it on the motorcycle.

FUEL SYSTEM 3-19

Carburetor

Carburetor Inspection

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Remove the carburetor.

•

Before disassembling the carburetor, check the fuel level

(see Fuel Level Inspection).

If the fuel level is incorrect, inspect the rest of the carbu-

retor before correcting it.

•

Pull the carburetor cable to check that the throttle valve

[A] moves smoothly and returns by spring pressure.

If the throttle valve does not move smoothly. Replace the

carburetor.

•

Disassemble the carburetor.

•

Clean the carburetor.

•

Check the O-rings on the float bowl, pilot screw, and throt-

tle sensor are in good condition.

If any of the O-rings are not in good condition, replace

them.

•

Check the tapered portion [A] of the pilot screw [B] for

wear or damage.

If the pilot screw is worn or damaged on the tapered por-

tion, it will prevent the engine from idling smoothly. Re-

place it.

•

Remove the float valve needle.

•

Check the plastic tip [A] of the float valve needle [B] for

wear.

If the needle is worn as shown right [C], replace the valve

needle.

•

Push the rod [D] in the valve needle, then release it.

If the rod does not come out fully by spring tension, re-

place the valve needle.

Push and release [E]

3-20 FUEL SYSTEM

Carburetor

•

Remove the slow jet.

•

Check the slow jet for any damage.

If the s low jet is damaged, replace it with a new one.

•

Remove the throttle valve and jet needle.

•

Inspect the outside of the throttle valve for scratches and

abnormal wear.

If it is badly scratched or worn, replace the throttle valve.

•

Inspect the inside of the carburetor body for these same

faults.

If it is badly scratched or worn, replace the entire carbu-

retor.

•

Check the jet needle for wear.

A worn jet needle should be replaced.

•

Clean the fuel and air passages with a high flash-point

solvent and compressed air.

FUEL SYSTEM 3-21

Air Cleaner

Housing Removal

•

Remove:

Side Covers

Seat

Muffler (see Engine Top End chapter)

Bolts and Rear Fender [A]

Screws and Rear Flap [B]

Rear Frame Mounting Bolts [C]

•

Loosen the air cleaner duct clamp [D].

•

Remove the rear frame with the air cleaner housing [E].

•

Unscrew the air cleaner housing bolts [F].

•

Remove the air cleaner housing.

Air Cleaner Housing Installation

•

Installation is the reverse of the removal.

•

Install the air cleaner housing and tighten the bolts [A].

Torque - Air Cleaner Housing Bolts: 8.8 N·m (0.90 kgf·m, 78

ft·lb)

•

Tighten the rear frame mounting bolts [B].

Torque - Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m, 25

ft·lb)

Element Removal

•

Remove the seat.

•

Remove the wing bolt [A] and pull out the element [B].

•

Stuff a clean, lint-free towel into the carburetor so no dirt

is allowed to enter the carburetor.

•

Wipe out the inside of the air cleaner housing with a clean

damp towel.

CAUTION

Check inside of the inlet tract and carburetor for

dirt. If dirt is present, clean the intake tract and car-

buretor thoroughly. You may also need to replace

the element and seal the housing and inlet tract.

Element Installation

•

When installing the element, coat the lip of the element

with a thick layer of all purpose grease [A] to assure a

complete seal against the air cleaner element base. Also,

coat the base where the lip of the element fits.

•

Apply grease to all connections and screw holes in the air

cleaner housing and intake tract.

•

Take out the towel from the carburetor securely.

3-22 FUEL SYSTEM

Air Cleaner

•

Install the element so that its tab [A] faces upward and fit

the element projections [B] to the holes of the housing [C].

Element Cleaning and Inspection

•

Refer to the Air Cleaner Element Cleaning and Inspection

in the Periodic Maintenance chapter.

FUEL SYSTEM 3-23

Fuel Tank

Fuel Tank Removal

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Always stop the

engine and do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Remove:

Radiator Shrouds

Seat

•

Turn the fuel tap to the OFF position.

•

Pull the fuel hose off the fuel tap.

•

Remove the fuel tank mounting bolt [A] and band [B].

•

Remove the fuel tank breather hose [C].

•

Remove the fuel tank [D].

•

Drain the fuel tank.

Fuel Tank Installation

•

Check the rubber dampers [A] on the frame.

If the dampers are damaged or deteriorated, replace

them.

•

Be sure the fuel hose is clamped to the fuel tap to prevent

leaks.

•

Insert the fuel tank breather hose outlet end into the steer-

ing stem hole (see Appendix chapter).

Fuel Tap Removal

•

Remove the fuel tank and drain it.

•

Remove the mounting bolts [A] and take out the fuel tap

[B].

Fuel Tap Installation

•

Be sure the O-ring is in good condition to prevent leaks.

•

Be sure to clamp the fuel hose to the tap to prevent leaks.

Fuel Tap Inspection

•

Refer to the in the Periodic Maintenance chapter.

Fuel Tank and Tap Cleaning

•

Refer to the Fuel Tank and Tap Cleaning in the Periodic

Maintenance chapter.

3-24 FUEL SYSTEM

Reed Valve

Reed Valve Removal

•

Remove the reed valve in accordance with the following

procedure.

KX125

○

Remove the carburetor, holder mounting bolts, and car-

buretor holder.

○

Remove the reed valve [A] out of the crankcase.

KX250

○

Drain the coolant.

○

Remove the carburetor and coolant hose [A].

○

Remove the holder mounting bolts [B], and take off the

carburetor holder [C].

○

Take the reed valve [A] out of the cylinder.

Reed Valve Installation

•

For KX125, install the reed valve [A] as shown.

Upward [B]

•

For KX250, install the reed valve [A] so that the ”↑”marked

side [B] faces upward.

•

Tighten the carburetor holder mounting bolts.

Torque - Carburetor Holder Mounting Bolts: 8.8 N·m (0.9

kgf·m, 78 in·lb)

Reed Valve Inspection

•

Refer to the Reed Valve Inspection in the Periodic Main-

tenance chapter.

COOLING SYSTEM 4-1

Cooling System

Table of Contents

Exploded View........................................................................................................................ 4-2

Specifications ......................................................................................................................... 4-6

Special Tool ............................................................................................................................ 4-7

Coolant ................................................................................................................................... 4-8

Coolant Level Inspection ................................................................................................... 4-8

Coolant Deterioration Inspection....................................................................................... 4-8

Coolant Draining ............................................................................................................... 4-8

Coolant Filling ................................................................................................................... 4-8

Air Bleeding....................................................................................................................... 4-8

Cooling System Pressure Testing ..................................................................................... 4-8

Cooling System Flushing .................................................................................................. 4-9

Disassembly and Assembly Precautions................................................................................ 4-10

Water Pump............................................................................................................................ 4-11

Water Pump Cover Removal ............................................................................................ 4-11

Water Pump Cover Installation ........................................................................................ 4-11

Impeller R emoval .............................................................................................................. 4-11

Impeller Installation ........................................................................................................... 4-11

Impeller Inspection............................................................................................................ 4-12

Water Pump Shaft Removal ............................................................................................. 4-12

Water Pump Shaft Installation .......................................................................................... 4-12

Oil Seal Removal .............................................................................................................. 4-12

Oil Seal Installation ........................................................................................................... 4-13

Radiator.................................................................................................................................. 4-14

Radiator Removal ............................................................................................................. 4-14

Radiator Installation .......................................................................................................... 4-14

Radiator Inspection ........................................................................................................... 4-15

Cap Inspection .................................................................................................................. 4-16

Filler Neck Inspection........................................................................................................ 4-16

Cooling Hoses, Breather Hose Inspection ........................................................................ 4-16

Cooling Hoses, Breather Hose Installation ....................................................................... 4-16

4-2 COOLING SYSTEM

Exploded View

KX125:

COOLING SYSTEM 4-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Water Pump Cover Bolts 8.8 0.9 78 in·lb

2 Coolant Drain Plug 8.8 0.9 78 in·lb

3 Water Pump Impeller Bolt 6.9 0.7 61 in·lb

4 Right Engine Cover Bolts 8.8 0.9 78 in·lb

5 Radiator Shroud Bolts 8.8 0.9 78 in·lb

6 Radiator Mounting Bolts 8.8 0.9 78 in·lb

7 Radiator Screen Bolts 8.8 0.9 78 in·lb

8 Radiator Bracket Bolts 8.8 0.9 78 in·lb

9 Cooling Hose Clamp Screws 1.5 0.15 13 in·lb

10. Radiator

11. Radiator Cap

12. Water Pump Cover

13. Impeller

14. Oil Seal (Short)

15. Oil Seal (Long)

16. Bearing

17. Water Pump Gear

18. Right Engine Cover

19. Cylinder Head

20. Cylinder

G: Apply grease.

M: Apply m olybdenum disulfide grease.

4-4 COOLING SYSTEM

Exploded View

KX250:

COOLING SYSTEM 4-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Water Pump Cover Bolts 8.8 0.9 78 in·lb

2 Water Pump Cover Fitting Bolts 5.9 0.6 52 in·lb

3 Coolant Drain Plug 8.8 0.9 78 in·lb

4 Water Pump Impeller Bolt 6.9 0.7 61 in·lb

5 Right Engine Cover Bolts 8.8 0.9 78 in·lb

6 Coolant Drain Plug (Cylinder) 8.8 0.9 78 in·lb

Cooling Hose Elbow Fitting Bolts

8.8 0.9 78 in·lb

8 Radiator Shroud Bolts 8.8 0.9 78 in·lb

9 Radiator Mounting Bolts 8.8 0.9 78 in·lb

Radiator Screen Bolts

8.8 0.9 78 in·lb

11 Radiator Bracket Bolts 8.8 0.9 78 in·lb

12 Cooling Hose Clamp Screws 1.5 0.15 13 in·lb

13. Radiator

14. Radiator Cap

15. Water Pump Cover

16. Impeller

17. Oil Seal (Short)

18. Oil Seal (Long)

19. Bearing

20. Water Pump Gear

21. Right Engine Cover

22. Cylinder Head

23. Cylinder

24. Elbow Fitting

G: Apply grease.

M: Apply m olybdenum disulfide grease.

4-6 COOLING SYSTEM

Specifications

Item Service Limit

Coolant

Type Permanent type antifreeze for aluminum engines and radiators

Color Green

Mixed Ratio Soft water 50%, antifreeze 50%

Total Amount:

KX125 0.97 L (1.02 US qt.)

KX250 1.20 L (1.27 US qt.)

Radiator

Cap Relief Pressure 93 ∼ 123 kPa (0.95 ∼ 1.25 kgf/cm², 13 ∼ 18 psi)

COOLING SYSTEM 4-7

Special Tool

Bearing Driver Set:

57001-1129

4-8 COOLING SYSTEM

Coolant

Check the coolant level each day before riding the motor-

cycle, and replenish coolant if the level is low. Change the

coolant in accordance with the Periodic Maintenance Chart

(see Periodic Maintenance chapter).

WARNING

To avoid burns, do not remove the radiator cap

or try to inspect the coolant level or change the

coolant when the engine is still hot. Wait until it

cools down.

Coolant Level Inspection

•

Refer to the Coolant Level Inspection in the Periodic Main-

tenance chapter.

Coolant Deterioration Inspection

•

Refer to the Coolant Deterioration Inspection in the Peri-

odic Maintenance chapter.

Coolant Draining

•

Refer to the Coolant Draining in the Periodic Maintenance

chapter.

Coolant Filling

•

Refer to the Coolant Filling in the Periodic Maintenance

chapter.

Air Bleeding

•

Refer to the Air Bleeding in the Periodic Maintenance

chapter.

Cooling S ystem Pressure Testing

CAUTION

During pressure testing, do not exceed the pres-

sure for which the system is designed to work. The

maximum pressure is 123 kPa (1.25 kgf/cm², 18 psi).

•

Remove the radiator cap, and install a cooling system

pressure tester [A] and adapter [B] on the radiator filler

neck [C].

NOTE

○

Wet the adapter cap sealing surfaces with water or

coolant to prevent pressure leaks.

•

Builduppressureinthesystemcarefullyuntilthepres-

sure reaches 123 kPa (1.25 kgf/cm², 18 psi).

•

Watch the gauge for at least 6 seconds. If the pressure

holds steady, the cooling system i s all right.

•

Remove the pressure tester, replenish the coolant, and

install the radiator cap.

If the pressure drops and no external source is found,

check for internal leaks. Check the cylinder head gasket

for leaks.

COOLING SYSTEM 4-9

Coolant

Cooling System Flushing

Over a period of time, the cooling system accumulates

rust, scale, and lime in the water jacket and radiator. When

this accumulation is suspected or observed, flush the cool-

ing system. If this accumulation is not removed, it will clog

up the water passages and considerably reduce the effi-

ciency of the cooling system.

•

Drain the cooling system.

•

Fill the cooling system with fresh water mixed with a flush-

ing compound.

CAUTION

Avoid the use of a flushing compound which is

harmful to the aluminum engine and radiator.

Carefully follow the instructions supp lied by the

manufacture of the cleaning product.

•

Warm up the engine, and run it at normal operating tem-

perature for about ten minutes.

•

Stop the engine, and drain the cooling system after the

coolant cools down.

•

Fill the system with fresh water.

•

Warm up the engine and drain the system after the

coolant cools down.

•

Repeat the previous two steps once more.

•

Fill the system with a permanent type coolant, and bleed

the air from the system (see Air Bleeding).

4-10 COOLING SYSTEM

Disassembly and Assembly Precautions

•

Prior to disassembly of cooling system parts (radiator,

pump, etc), wait until the coolant cools down, and then

drain the coolant.

•

After assembling and filling the system with coolant, bleed

any air from the system.

COOLING SYSTEM 4-11

Water Pump

Water Pump Cover Removal

•

Drain the coolant (see Coolant Draining).

•

Loosen the cooling hose clamps [A], and disconnect the

cooling hoses on the water pump cover [B].

•

Unscrew the cover bolts [C], and remove the water pump

cover.

Water Pump Cover Installation

•

Replace the pump cover gasket with a new one.

•

Tighten the water pump cover bolts and clamps.

Torque - Water Pump Cover Bolts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Cooling Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,

13 in·lb)

•

Fill the c ooling system (see Coolant Filling).

•

Bleed the air from the cooling system.

Impeller Removal

•

Drain the coolant (see Coolant Draining).

•

Remove the cover bolts and take out the water pump

cover from the right engine cover with the cooling hoses

attached.

•

Remove the impeller bolt [A], and take out the impeller [B]

and washer.

Impeller Installation

•

Tighten the impeller bolt.

Torque - Impeller Bolt: 6.9 N·m (0.7 kgf·m, 61 in·lb)

4-12 COOLING SYSTEM

Water Pump

Impeller Inspection

•

Visually check the impeller [A].

If the surface is corroded, or if the blades [B] are dam-

aged, replace the impeller.

Water Pump Shaft Removal

•

Remove:

Right Engine Cover (see Engine Right Side chapter)

•

Pull out the water pump shaft [A] toward inside of the right

engine cover.

Water Pump Shaft Installation

•

To prevent the oil seal lips from peeling, apply a molybde-

num disulfide grease [A] to the water pump shaft [B] and

insert it into the oil seals [C] from the inside of the right

engine cover [D].

CAUTION

Be sure to apply a molybdenum disulfide grease

to the water pump shaft when installing. If it is in-

stalled dry, the seals may wear excessively.

•

Instal the impeller and check to see that the impeller turn

freely.

Oil Seal Removal

•

Remove:

Right Engine Cover (see Engine Right Side chapter)

Water Pump Shaft

•

Insert a bar [A] into the water pump shaft hole from the

outside of the right engine cover, and remove the ball

bearing [B] by tapping [C] evenly around the bearing in-

ner race.

COOLING SYSTEM 4-13

Water Pump

•

Insert a bar [A] into the water pump shaft hole from the

inside of the right engine cover, and remove the oil seal

[B] by tapping [C] evenly around the seal lips.

Oil Seal Installation

CAUTION

If the oil seal or ball bearing is removed, replace all

of them with new ones at the same time

•

Be sure to replace the oil seals.

•

Apply plenty of high temperature grease to the oil seal lips

[A].

•

Press the oil s eals [B] into the hole from the outside of the

right engine cover.

Special Tool - Bearing Driver Set: 57001-1129

•

Set the oil seal (thick) so that dual lips side face outward

and set the oil seal (thin) so that a lip faces outward as

shown.

NOTE

○

Use a bearing driver larger in diameter than the oil seal,

and press the oil seal into the hole until the edge of the

oil seal located 0.1

∼

0.5 mm (0.0039

∼

0.0197 in.) [D]

deep from the surface of the hole.

•

Press the ball bearing into the hole until the bearing is

bottomed against the step [E].

Special Tool - Bearing Driver Set: 57001-1129

4-14 COOLING SYSTEM

Radiator

Radiator Removal

•

Drain the coolant (see Coolant Draining)

•

Remove:

Radiator Shrouds

Fuel Tank (see Fuel System chapter)

•

Unscrew the clamps [A] and the bolts [B].

•

Remove the radiator screens [C].

•

Unscrew the bolts [A].

•

Remove:

Radiator Brackets [B]

Radiator [C] with the cooling hoses

○

For KX125 be sure to remove the magneto lead (harness)

from left radiator.

Radiator Installation

•

Radiator installation is the reverse of removal.

•

Tighten:

Torque - Cooling Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,

13 in·lb)

Radiator Bracket Bolts: 8.8 N·m (0.90 kgf·m, 78

in·lb)

Radiator Mounting Bolts 8.8 N·m (0.90 kgf·m, 78

in·lb)

Radiator Screen Bolts 8.8 N·m (0.90 kgf·m, 78

in·lb)

Radiator Shroud Bolts 8.8 N·m (0.90 kgf·m, 78

in·lb)

•

Route the cooling and breather hoses correctly.

COOLING SYSTEM 4-15

Radiator

Radiator Inspection

•

Check the radiator core.

If there are obstructions to air flow, remove them.

If the corrugated fins are deformed, carefully straighten

them with the thin blade of a screwdriver [A].

CAUTION

Do not tear the radiator tubes while straightening

the fins.

If the air passages of the radiator core are blocked more

than 20% by unremovable obstructions or irreparably de-

formed fins, replace the radiator with a new one.

CAUTION

When cleaning the radiator with steam cleaner, be

careful of the following to prevent radiator damage.

Keep the steam gun [C] away more than 0.5 m (1.64

ft) [B] from the radiator core. Hold the steam gun

perpendicular to the core surface. Run the steam

gun following the core fin direction [A].

4-16 COOLING SYSTEM

Radiator

Cap Inspection

•

Check the condition of the valve spring [B], and the top

and bottom valve seals [A] of the radiator cap.

If any one of them shows visible damage, replace the cap.

•

Wet the top and bottom valve seals with water or coolant

to prevent pressure leaks.

•

Install the cap [A] on a cooling system pressure tester [B].

•

Watching the pressure gauge, slowly pump the pressure

tester to build up the pressure. The gauge hand must

remain within the relief pressure range in the table below

at least 6 seconds. Continue to pump the tester until the

relief valve opens, indicated by the gauge hand flicking

downward. The relief valve must open within the specified

range.

Radiator Cap Relief Pressure:

Standard: 93 ∼ 123 kPa (0. 95 ∼ 1.25 kgf/cm², 13 ∼ 18 psi)

If the cap cannot hold the pressure, or if the relief pressure

is too high o r too low, replace the cap with a new one.

Filler Neck Inspection

•

Check the radiator filler neck for signs of damage.

•

Check the condition of the top and bottom sealing seats

[A] in the filler neck. They must be smooth and clean for

the radiator cap to function properly.

Cooling Hoses, Breather Hose Inspection

•

Refer to the Cooling Hoses and Connections Inspection

in the Periodic Maintenance chapter.

Cooling Hoses, Breather Hose Installation

•

Install the cooling hoses or breather hose being careful

to follow the performed bends (see Appendix chapter).

Avoid sharp bending, kinking, flattening, or twisting.

•

Tighten the hose clamps s ecurely.

Torque - Cooling Hose Clamp Screws: 1.5 N·m (0.15 kgf·m,

13 in·lb)

ENGINE TOP END 5-1

Engine Top End

Table of Contents

Exploded View........................................................................................................................ 5-2

Specifications ......................................................................................................................... 5-6

Special Tools .......................................................................................................................... 5-7

Cylinder Head......................................................................................................................... 5-8

Cylinder Compression Measurement................................................................................ 5-8

Cylinder Head Removal .................................................................................................... 5-8

Cylinder Head Installation ................................................................................................. 5-9

Cylinder Head Warp Inspection ........................................................................................ 5-9

Cylinder .................................................................................................................................. 5-10

Cylinder Removal.............................................................................................................. 5-10

Cylinder Installation........................................................................................................... 5-11

Piston Removal................................................................................................................. 5-12

Piston Installation..............................................................................................................5-12

Cylinder Wear Inspection.................................................................................................. 5-13

Piston Diameter Measurement ......................................................................................... 5-14

Piston/Cylinder Clearance ................................................................................................ 5-14

Piston Ring, Piston Ring Groove Inspection ..................................................................... 5-14

Piston Ring End Gap Inspection ....................................................................................... 5-14

Piston, Piston Pin, Connecting Rod Wear Inspection ....................................................... 5-14

Exhaust Valve (KIPS) ............................................................................................................. 5-15

Exhaust Valve Removal (KX125 Model) ........................................................................... 5-15

Exhaust Valve Removal (KX250 Model) ........................................................................... 5-16

Exhaust Valve Installation (KX125 Model) ........................................................................ 5-17

Exhaust Valve Installation (KX250 Model) ........................................................................ 5-19

Muffler (Expansion Chamber, Muffler Body)........................................................................... 5-24

Muffler Removal................................................................................................................ 5-24

Muffler Installation.............................................................................................................5-24

Muffler Baffle Change ....................................................................................................... 5-24

5-2 ENGINE TOP END

Exploded View

KX125:

ENGINE TOP END 5-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

Main Valve Cover Bolts

5.9 0.6 52 in·lb

2 Cylinder Head Nuts 25 2.5 18

3 Spark Plug 26.5 2.75 19.5

Engine Mounting Bracket Nut (Engine Side 10 mm)

(KX125-M1) 44 4.5 334

(KX125-M2∼) 49 5.0 36

Engine Mounting Bracket Nuts (Frame Side 8 mm)

29 3.0 22

KIPS Cover Bolts

(KX125-M1) 4.9 0.5 43 in·lb6

(KX125-M2∼) 8.8 0.9 78 in·lb

7 Cylinder Nuts 25 2.5 18

8 Governor Shaft Lever Mounting Bolt 6.9 0.7 61 in·lb

Main Shaft Stopper Pin Plug

0.8 0.08 6.9 in·lb

10 Main Lever Mounting Allen Bolt 3.9 04 35 in·lb L

11 Exhaust Valve Retaining Bolts 5.9 0.6 52 in·lb

12 Muffler Pipe Mounting Bolts 8.8 0.9 78 in·lb L

13 Inner Pipe Mounting Bolts 8.8 0.9 78 in·lb L

14 Muffler Damper Mounting Bolts 8.8 0.9 78 in·lb

15 Expansion Chamber Mounting Bolt 12 1.2 8.7

16 Muffler Mounting Bolts 8.8 0.9 78 in·lb

17. Main Valve C over

18. Cylinder Head

19. Engine Mounting Brackets

20. KIPS Cover

21. Piston Ring

22. Piston

23. “R” Mark

24. “Alphabet” Mark

25. Piston Pin

26. Cylinder

27. Main Shaft

28. Main Lever

29. Spring

30. Exhaust Valve Retaining Plate

31. Governor Shaft Lever

32. Exhaust Valve Right (Identification Slot)

33. Exhaust Valve Left

34a. Expansion Chamber (KX125-M1 model)

34b. Expansion Chamber (KX125-M2 model ∼)

35. Rubber Seals

36. Muffler Body

G: Apply grease.

L: Apply a non-permanent locking agent.

M: Apply molybdenum disulfide grease.

O: Apply 2-stroke engine oil.

SS: Apply silicone sealant.

5-4 ENGINE TOP END

Exploded View

KX250:

ENGINE TOP END 5-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

Cylinder Head Nuts

25 2.5 18

2 Spark Plug 26.5 2.75 19.5

3 Main Valve Cover Bolts 5.9 0.6 52 in·lb

4 Main Valve Retaining Bolts 5.9 0.6 52 in·lb

5 Main Valve Rod Cover Screw 5.9 0.6 52 in·lb

6 Main Lever Mounting Allen Bolt 3.9 0.4 35 in·lb L

Operating Rod Retaining Screw

5.4 0.55 48 in·lb

8 Coolant Drain Plug (Cylinder) 8.8 0.9 78 in·lb

9 Cylinder Nuts 34 3.5 25

10 Operating Rod Left Side Plug 22 2.2 16

11 Cylinder Left Cover Bolts 5.9 0.6 52 in·lb

12 KIPS Cover Bolts 2.9 0.3 26 in·lb

Engine Mounting Bracket Nuts (Frame Side 8 mm)

29 3.0 22

Engine Mounting Bracket Nuts (Engine Side 10 mm)

(KX250-M1) 44 4.5 3314

(KX250-M2 ∼) 49 5.0 36

15 Muffler Pipe Mounting Bolts 8.8 0.9 78 in·lb L

16 Inner Pipe Mounting Bolts 8.8 0.9 78 in·lb L

17 Muffler Damper Mounting Bolts 8.8 0.9 78 in·lb

18 Expansion Chamber Mounting Bolt 12 1.2 8.7

19 Muffler Mounting Bolts 8.8 0.9 78 in·lb

20. Cylinder Head

21. Engine Mounting Brackets

22. Governor Shaft Lever

23. KIPS Cover

24. Operating Rod

25. Main Valve Cover

26. Main Lever

27. Spring

28a. Main Exhaust Valve Assembly

(KX250-M1 model)

28b. Main Exhaust Valve Assembly

(KX250-M2 model ∼)

29. Main Valve Rod Cover

30. Main Valve Rod

31. Main Shaft

32. Cylinder Left Cover

33. Cylinder

34. Exhaust Valve (Left)

35. Exhaust Valve (Right)

36. Guide

37. O-ring

38. Idle Gear

39. Guide

40. Piston Ring

41. Piston

42. “IN” Mark

43. Piston Pin

44. Reed Valve

45a. Expansion Chamber

(KX250-M1 model)

45b. Expansion Chamber

(KX250-M2 model ∼)

46. Rubber Seals

47. Gasket

48. Muffler Body

49. Vent Hose (KX250-M2 model ∼)

G: Apply g rease.

L: Apply a non-permanent locking agent.

M: Apply molybdenum disulfide grease.

O: Apply 2-stroke engine oil.

SS: Apply silicone sealant.

5-6 ENGINE TOP END

Specifications

KX125:

Item

Standard Service Limit

Cylinder Head

Cylinder Compression (Usable range) –––

890 ∼ 1 370 kPa

(9.1 ∼ 14.0 kgf/cm², 129 ∼ 199 psi)

Cylinder Head Warp ––– 0.03 mm (0.0012 in.)

Cylinder, Piston

Cylinder Inside Diameter (15

mm (0.59 in.) below of the

cylinder head)

54.010 ∼ 54.025 mm (2.1264 ∼ 2.1270 in.) 54.10 mm (2.130 in.)

Piston Diameter 53.955 ∼ 53.970 mm (2.1242 ∼ 2.1248 in.) 53.81mm(2.118in.)

Piston/Cylinder Clearance 0.040 ∼ 0.070 mm (0.0016 ∼ 0.0028 in.) –––

Piston Ring/Groove Clearance 0.015 ∼ 0.050 mm (0.0006 ∼ 0.0020 in.) 0.15 mm (0.006 in.)

Piston Ring Groove Width 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.) 1.11 mm (0.044 in.)

Piston Ring Thickness 0.980 ∼ 0.995 mm (0.0386 ∼ 0.0392 in.) 0.91 mm (0.036 in.)

Piston Ring End G ap 0.35 ∼ 0.55 mm (0.0138 ∼ 0.0217 in.) 0.85 mm (0.033 in.)

Piston Pin Diameter 14.995 ∼ 15.000 mm (0.5904 ∼ 0.5906 in.) 14.96 mm (0.589 in.)

Piston Pin Hole Diameter 15.001 ∼ 15.011 mm (0.5906 ∼ 0.5910 in.) 15.08 mm (0.594 in.)

Small End Inside Diameter 19.003 ∼ 19.014 mm (0.7481 ∼ 0.7486 in.) 19.05 mm (0.750 in.)

KX250:

Item Standard Service Limit

Cylinder Head

Cylinder Compression (Usable range) –––

825 ∼ 1275kPa

(8.4 ∼ 13.0 kgf/cm², 119 ∼ 185 psi)

Cylinder Head Warp ––– 0.03 mm (0.0012 in.)

Cylinder, Piston

Cylinder Inside Diameter 66.400 ∼ 66.415 mm (2.6142 ∼ 2.6148 in.) 66.46 mm (2.617 in.)

30 mm (1.18 in.) below of the

cylinder head)

Piston Diameter

66.336 ∼ 66.351 mm (2.6116 ∼ 2.6122 in.) 66.19 mm (2.6059 in.)

Piston/Cylinder Clearance 0.049 ∼ 0.079 mm (0.0019 ∼ 0.0031 in.)

–––

Piston Ring/Groove Clearance 0.025 ∼ 0.06 mm (0.00098 ∼ 0.00236 in.) 0.16 mm (0.006 in.)

Piston Ring Groove Width 1.01 ∼ 1.03 mm (0.0398 ∼ 0.0406 in.) 1.11 mm (0.044 In.)

Piston Ring Thickness 0.970 ∼ 0.985 mm (0.0382 ∼ 0.0388 in.) 0.90 mm (0.035 in.)

Piston Ring End Gap 0.25 ∼ 0.45 mm (0.0098 ∼ 0.0177 in.) 0.75 mm (0.030 in.)

Piston Pin Diameter

17.995 ∼ 18.000 mm (0.7085 ∼ 0.7087 in.) 17.96 mm (0.707 in.)

Piston Pin Hole Diameter

18.001 ∼ 18.011 mm (0.7087 ∼ 0.7091 in.) 18.08 mm (0.712 in.)

Small End Inside Diameter 22.003 ∼ 22.012 mm (0.8663 ∼ 0.8666 in.) 22.05 mm (0.868 in.)

ENGINE TOP END 5-7

Special Tools

Compression Gauge, 20 kgf/cm²:

57001-221

Piston Pin Puller Assembly:

57001-910

Compression Gauge Adapter, M14 × 1.25:

57001-1159

5-8 ENGINE TOP END

Cylinder Head

Cylinder Compression Measurement

•

Start the engine.

•

Thoroughly warm up the engine so that the engine oil be-

tween the piston and cylinder wall will help seal compres-

sion as it does during normal running.

•

Stop the engine.

•

Remove the fuel tank (see Fuel System chapter).

•

Remove the spark plug, and screw a compression gauge

firmly into the spark plug hole.

Special Tools - Compression Gauge, 20 kgf/cm²: 57001-221

[A]

Compression Gauge Adapter, M14 × 1.25:

57001-1159

•

With the throttle fully open, turn the engine over sharply

with the kickstarter several times until the compression

gauge stops riding; the compression is the highest read-

ing obtainable.

Cylinder Compression

Usable Range:

KX125

890 ∼ 1 370 kPa (9.1 ∼ 14.0 kgf/cm², 129 ∼

199 psi)

KX250

825 ∼ 1 275 kPa (8.4 ∼ 13.0 kgf/cm², 119 ∼

185 psi)

If cylinder compression is higher than the usable range,

check the following:

1. Carbon build up on the piston head and cylinder head -

clean off any carbon on the piston head.

2. Cylinder head gasket, cylinder base gasket - use only

the proper gaskets for the cylinder head and base. The

use of gasket of the incorrect thickness will change the

compression.

If cylinder compression is lower than the usable range,

check the following:

1. Piston/cylinder clearance, piston seizure.

2. Gas leakage around the cylinder head - replace the

damaged gasket and check the cylinder head for warp-

ing.

3. Piston ring, piston ring groove.

Cylinder Head Removal

•

Drain the coolant (see Cooling System chapter).

•

Remove:

Radiator Shrouds

Seat

Side Covers

Fuel Tank (see Fuel System chapter)

Muffler (see this chapter)

Radiators (see Cooling System chapter )

Cooling Hose [A]

Spark Plug [B]

Bolts & Nuts [C]

Engine Mounting Brackets [D]

ENGINE TOP END 5-9

Cylinder Head

•

Remove the cylinder head nuts [A], and take off the

cylinder head [B] and the O-rings (KX125) or the gasket

(KX250).

Cylinder Head Installation

•

Replace the O-rings or the head gasket with a new one.

•

Scrape out any carbon and clean the head with a high

flash-point solvent.

•

Check for a crust of minerals and rust in the head water

jacket, and remove them if necessary.

•

For KX125, install new O-rings to the grooves of the cylin-

der securely.

•

For KX250, install a new cylinder head gasket with the EX

marked side [A] forward.

•

Tighten the head nuts diagonally.

Torque - Cylinder Head Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)

•

Tighten the engine mounting bracket nuts.

Torque - Cylinder Head Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)

Engine Mounting Bracket Nuts:

10 mm: 44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250

-M1)

49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250

-M2 ∼)

8mm:29N·m(3.0kgf·m,22ft·lb)

•

Tighten the spark plug.

Torque - Spark Plug: 26.5 N·m (2.75 kgf·m, 19.5 ft·lb)

Cylinder Head Warp Inspe ction

•

Refer to the Cylinder Head Warp Inspection in the Peri-

odic Maintenance c hapter.

5-10 ENGINE TOP END

Cylinder

Cylinder Removal

•

Drain the coolant (see Cooling System chapter).

○

For KX250: be sure to remove the cylinder drain plug.

•

Remove the cylinder head (see this chapter).

•

Remove the cooling hoses.

•

Remove the KIPS cover [A] at the cylinder.

•

Remove the governor shaft lever in accordance with the

following procedure .

KX125

○

Remove the bolt [A] and pull out the governor shaft lever

[B] from the main shaft.

KX250

○

Loosen the clamps, and pull the carburetor out of the

holder and the air cleaner duct.

○

Remove the E-clip [A] from the operating rod.

○

Put a 9 mm (0.35 in.) spanner wrench [A] on the governor

shaft lever upper end.

○

Turn the governor shaft lever [B] counterclockwise with

the wrench, and take off the operating rod collar [C] by

pushing the operating rod into the cylinder.

○

Before pulling the governor shaft lever [A] free, turn the

remaining E-clip [B] to a suitable position as shown in the

figure to prevent the governor shaft l ever boss [C] and the

E-clip from hitting.

ENGINE TOP END 5-11

Cylinder

•

For KX250, remove the magneto lead and the clutch ca-

ble from clamp.

•

Remove the cylinder nuts [A].

•

Lift off the cylinder, and remove the cylinder base gasket.

If necessary, tap lightly around the base of the cylinder

with a p lastic mallet [A], taking care not to damage the

cylinder.

•

Remove the exhaust valves from the cylinder (see Ex-

haust Valve Removal).

Cylinder Installation

•

Scrape any carbon out of the exhaust port.

•

Check on a crust of minerals and rust in the cylinder water

jacket, and remove them if necessary.

•

Replace the cylinder base gasket with a new one.

•

Apply engine oil to the piston surface, piston rings and

cylinder bore.

•

Check to see that the pin [A] in each piston ring groove

is between the ends of the piston ring, and fit the base of

the cylinder over each ring, pressing in on opposite sides

of the ring as necessary. Be certain that the rings do not

slip out of position.

•

Tighten the cylinder nuts diagonally.

Torque - Cylinder Nuts:

KX125: 25 N·m (2.5 kgf·m, 18 ft·lb)

KX250: 34 N·m (3.5 kgf·m, 25 ft·lb)

KX125

•

Using the 14 mm (0.56 in.) spanner wrench [A], turn the

governor shaft counterclockwise.

•

Install the governor shaft lever [B] to the main shaft and

tighten the bolt [C].

Torque - Governor S haft Lever Mounting Bolt: 6.9 N·m (0.7

kgf·m, 61 in·lb)

•

Install the KIPS cover.

•

Tighten:

Torque - KIPS Cover Bolts:

KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)

KX125-M2 ∼: 8.8 N·m (0.9 kgf·m, 78 in·lb )

5-12 ENGINE TOP END

Cylinder

KX250

•

Install the governor shaft lever and operating rod collar in

accordance with the following procedure.

○

Put a 9 mm (0.35 in.) spanner [A] wrench on the governor

shaft lever upper end.

○

Turn the governor shaft lever counterclockwise with the

wrench and fit the groove of the operating rod collar [B] to

the boss of the governor shaft lever, and install the collar

on the operating rod while holding the governor shaft lever

clockwise.

•

After installing the collar, install the E-clip [A] on the oper-

ating rod [B].

•

Install the KIPS cover.

•

Tighten:

To rque - KIPS Cover Bolts: 2.5 N·m (0.25 kgf·m, 22 in·lb)

Piston Removal

•

Remove the cylinder.

•

Stuff a clean cloth into the crankcase opening around the

connecting rod so that no parts will fall into the crankcase.

•

Remove one of the piston pin snap rings with needle nose

pliers.

•

Remove the piston by pushing the piston pin out the side

from which the snap ring was removed. Use a piston pin

puller assembly [A], if the pin is tight.

Special Tool - Piston Pin Puller Assembly: 57001-910

•

Remove the piston ring(s).

○

Carefully spread the ring [A] opening with your thumbs

and then push up on the opposite side of the ring to re-

move it.

Piston Installation

•

Stuff a clean cloth into the crankcase opening around the

connecting rod so that no parts will fall into the crankcase.

•

Scrape off any carbon of the piston, then lightly polish the

piston with fine emery cloth.

•

Clean carbon and dirt out of the piston ring groove using

a suitable tool.

CAUTION

Carbon particles can be very abrasive to piston

ring. Don’t allow such particles to fall onto the

cylinder walls.

ENGINE TOP END 5-13

Cylinder

•

When installing the piston ring on the piston, note the fol-

lowing:

○

For KX250, the top [A] and second [B] rings are identical.

○

First fit one end of the piston ring against the pin in the

ring groove, spread the ring opening with the other hand

and then slip the ring into the groove.

○

For KX125, the piston ring have a “R” mark [A] on it upper

surface.

○

Install the ring so that the pin [A] in the piston ring groove

is between the ends of the piston ring.

•

Apply 2-stroke engine oil to the connecting rod needle

bearing and the piston pin.

•

For KX125, install the piston so that the “Alphabet”

marked side [A] faces the front side (Exhaust side) of the

engine.

•

For KX250, install the piston so that the “IN” marked side

[A] faces the back side of the engine.

•

When installing a piston pin snap ring [A], compress it only

enough to install it and no more.

CAUTION

Do not reuse snap rings, as removal weakens and

deforms them. They could fall out and score the

cylinder wall.

•

Fit a new piston pin snap ring into the side of the piston so

that the ring opening [B] does not coincide with the notch

[C] in the edge of the piston pin hole.

Cylinder Wear Inspection

•

Refer to the Cylinder Wear Inspection in the Periodic

Maintenance chapter.

5-14 ENGINE TOP END

Cylinder

Piston Diameter Measurement

•

Refer to the Piston Diameter Measurement in the Periodic

Maintenance chapter.

Piston/Cylinder Clearance

•

Refer to the Piston/Cylinder Clearance in the Periodic

Maintenance chapter.

Piston Ring, Piston Ring Groove Inspection

•

Refer to the Piston Ring, Piston Ring Groove Inspection

in the Periodic Maintenance chapter.

Piston Ring End Gap Inspection

•

Refer to the Piston Ring End Gap Inspection in the Peri-

odic Maintenance chapter.

Piston, Piston Pin, Connecting Rod Wear Insp ection

•

Refer to the Piston, Piston Pin, Connecting Rod Wear

Inspection in the Periodic Maintenance chapter.

ENGINE TOP END 5-15

Exhaust Valve (KIPS)

Exhaust Valve Removal (KX125 Model)

•

Drain the coolant.

•

Remove:

Radiator (see Cooling System chapter)

Muffler (see Muffler Removal)

KIPS Cover (see Engine Right Side chapter)

Bolt [A]

Governor Shaft Lever [B]

•

Remove:

Cylinder (see Cylinder Removal)

Main Valve Cover Bolts [A]

Main Valve Cover [B]

Stopper Pin S crew [A] and Stopper Pin [B]

Allen Bolt [C]

•

Pull out the main exhaust valve shaft [A] and remove the

main lever [B] with spring [C].

•

Remove the exhaust valve retaining bolts [A].

•

Pull out the exhaust valves [B].

5-16 ENGINE TOP END

Exhaust Valve (KIPS)

Exhaust Valve Removal (KX250 Model)

•

Remove:

Carburetor (see Fuel System chapter)

Cylinder Head (see Cylinder Head Removal)

•

Remove the KIPS cover at the cylinder

•

Remove the E-clip [A] and operating rod collar [B] from

the operating rod.

•

Remove the cylinder (see Cylinder Removal).

•

Turn the cylinder up side down.

•

Remove the plug [A] and the gasket [B] at the left side of

the cylinder.

•

Pull out the operating rod [A] as far as it goes.

•

Remove the operating rod retaining screw [B].

•

Remove the idle gear [A].

•

Lift up the exhaust valves [B], and remove the valve

guides [C].

•

Lift up the exhaust valves, and pull out the operating rod

[D]. Then take out the exhaust valves.

•

Remove the main valve cover [A], main valve rod cover

[B] and cylinder left cover [C] from the cylinder.

ENGINE TOP END 5-17

Exhaust Valve (KIPS)

•

Unscrew the Allen bolt [A] from the main lever [B].

•

Position the main exhaust valve full open, and pull out the

main shaft [C].

•

Set the main exhaust valve full closed position, and re-

move the main lever with spring [D].

•

Pull out the main valve rod [E] from the cylinder.

•

Unscrew the two main valve retaining bolts [A] and take

out the main exhaust valve assembly [B] from the cylinder.

Exhaust Valve Installation (KX125 Model)

•

Scrape out any carbon and clean the valves with a high

flash-point solvent.

•

Check the following for signs of damage:

Exhaust Valves

Oil Seal

Gaskets

If necessary, replace them with new ones.

•

Apply a 2-stroke engine oil to the operation parts.

•

Apply a high temperature grease to the oil seal lip.

•

Insert the exhaust valves [A] so that their spherical parts

[B] shall direct to downward.

NOTE

○

There are left and right sides for the exhaust valves.

○

Right exhaust valve has a identification slot [C] so that

it shall be installed upward.

•

Install the retaining plate [D] and tighten exhaust valve

retaining bolts [E].

Torque - Exhaust Valve Retaining Bolts: 5.9 N·m (0.6 kgf·m,

52 in·lb)

•

Check that the exhaust valves slide smoothly.

5-18 ENGINE TOP END

Exhaust Valve (KIPS)

•

Fit the spring [A] to the main lever [B].

•

Insert the main shaft [A] in the hole of the cylinder and

through the holes in the main lever [B] with spring [C].

•

Install the stopper pin [A].

•

Tighten:

Torque - Stopper Pin Plug: 0.8 N·m (0.08 kgf·m, 69 in·lb)

•

Apply a non-permanent locking agent to the Allen bolt [B].

•

Fix the main lever to the main shaft with the Allen bolt.

•

Tighten:

Torque - Main Lever Allen Bolt: 3.9 N·m (0.4 kgf·m, 35 in·lb)

•

Install the main valve cover.

•

Tighten:

Torque - Main Valve Cover Bolts: 5.9 N·m (0.6 kgf·m, 52

in·lb)

NOTE

○

When main shaft [A] turns clockwise and with the ex-

haust valves [B] fully opened position, check the end of

exhaust valves and the exhaust ports [C] are aligned

with.

ENGINE TOP END 5-19

Exhaust Valve (KIPS)

•

Install the cylinder (see Cylinder Installation).

•

Tighten:

Torque - Cylinder Nuts: 25 N·m (2.5 kgf·m, 18 ft·lb)

•

Using the 14 mm (0.56 in.) spanner wrench [A], install the

governor shaft lever [B] as shown.

•

Tighten:

Torque - Governor Shaft Lever Mounting Bolt [C]: 6.9 N·m

(0.7 kgf·m, 61 in·lb)

•

Install the KIPS cover.

•

Tighten:

Torque - KIPS Cover Bolts:

KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)

KX125-M2 ∼: 8.8 N·m (0.9 kgf·m, 78 in·lb )

•

Install the removal parts.

Exhaust Valve Installation (KX250 Model)

•

Remove any carbon and clean the valves with a high flash

-point solvent.

•

Check the following for signs of damage:

Exhaust Valves

Valve Operating Rod

Oil Seal on R od Seal Plug

O-rings

Gaskets

If necessary, replace damaged or worn items with new

ones.

•

Check the gasket on the left plug for signs of damage.

If necessary, replace it with new one.

•

Install the operating rod left side plug on the cylinder.

•

Tighten:

Torque - Operating Rod Left Side Plug: 22 N·m (2.2 kgf·m,

16.0 ft·lb)

•

Apply a 2-stroke engine oil to the following:

Valve Guides (inside)

Valve Operating Rod Journals

Valve Operating Rod Rack

Main Exhaust Valve Parts

•

Apply a high temperature grease to the oil seal lip on the

operating rod.

•

Set up the main exhaust valve assembly as shown.

Slide Valve [A]

Valve Holder [B]

•

Check the slide valve move smoothly.

5-20 ENGINE TOP END

Exhaust Valve (KIPS)

•

For KX250-M2 model∼; note the following.

○

Apply a 2-stroke engine oil to the main exhaust valve [A].

•

Insert the main exhaust valve assembly [A] into the cylin-

der [B].

•

Install the main valve retaining bolts [C] securely and

tighten them.

Torque - Main Valve Retaining Bolts: 5.9 N·m (0.6 kgf·m, 52

in·lb)

•

Check the main exhaust valve assembly slide smoothly.

•

Fit the spring [A] to the main lever [B].

•

Install the main lever [A] with spring to the slide valve pin

[B].

•

Install the main valve rod [C] in the cylinder so that the

grooved side [D] faces outward and the gear teeth face

down.

•

Insert the main shaft [A] into the hole of the left upper end

at the cylinder and through the hole in the main lever [B]

and spring [C]. Then put the main shaft into the cylinder

hole.

ENGINE TOP END 5-21

Exhaust Valve (KIPS)

•

Align the punch mark [A] on the main shaft gear with the

groove [B] on the main valve rod.

•

Turn the cylinder upside down.

•

Push [A] the main valve rod in until it is fully seated into

the cylinder.

•

Insert the sub exhaust valves partially into the cylinder

so that the operating rod can pass underneath the gears.

The right sub exhaust valve [A] is smaller than the left sub

exhaust valve.

•

Insert the operating rod until it is fully seated against the

plug on the opposite side of the cylinder, and push the oil

seal assembly into the cylinder.

•

Align the punch mark [B] (marked with red paint) on the

exhaust valve rods [A] with the grooves [C] in the operat-

ing rod.

NOTE

○

The marked tooth [A] is identified by i ts shape also.

[B] Punch Mark (Red Panjab)

5-22 ENGINE TOP END

Exhaust Valve (KIPS)

•

Insert the idle gear.

•

Apply high temperature grease to the O-ring.

•

Mount the valve guides [B, D] on the sub exhaust valves

[A] and idle gear [C].

•

Apply a non-permanent locking agent to the Allen bolt.

•

Fix the main lever [A] to the main shaft [B] with the Allen

bolt [C].

•

Tighten:

Torque - Main Lever Mounting Allen Bolt: 3.9 N·m (0.4

kgf·m, 35 in·lb)

•

Check that the main exhaust valve assembly slide

smoothly.

NOTE

○

When tighten the main lever mounting Allen bolt [A],

main exhaust valve assembly [B] should be in fully

closed position as shown.

•

For KX250-M2 model∼; as shown in the figure.

•

There are three checks to ensure the sub exhaust valves

are in the correct position:

○

With the sub exhaust valves in the fully closed position the

hole leading to the left side KIPS chamber is only partially

open [A].

ENGINE TOP END 5-23

Exhaust Valve (KIPS)

○

The distance from the top of t he operating rod collar to the

cylinder should be 14.5 ∼ 15.5 mm (0.57 ∼ 0.61 in.) [A].

○

In the fully open position with the main valve rod flush with

the cylinder [A], the sub exhaust valves will be aligned [B]

with the sub exhaust ports.

•

Check that the sub exhaust valves operate smoothly.

•

Install the operating rod retaining s crew securely.

•

Tighten:

Torque - Operating Rod Screw: 5.4 N·m (0.55 kgf·m, 48

in·lb)

•

Install the main valve cover, main valve rod cover and

cylinder left cover on the cylinder.

•

Tighten:

Torque - Main Valve Cover Bolts: 5.9 N·m (0.6 kgf·m, 52

in·lb)

Main Valve Rod Cover Screw: 5.9 N·m (0.6 kgf·m,

52 in·lb)

•

Install the removed parts.

5-24 ENGINE TOP END

Muffler (Expansion Chamber, Muffler Body)

Muffler Removal

•

Remove:

Right Radiator Shroud

Right Side Cover

•

Remove the m ounting bolts [A] and pull the muffler body

[B] off toward the rear.

•

Remove the exhaust pipe holding springs [A].

•

Remove the muffler damper mounting bolts [A], and pull

off the expansion chamber to the front ward.

•

Remove the O-rings from the expansion chamber.

○

For KX250: be sure to remove exhaust gasket.

•

For KX125/250-M2 model∼; as shown in the figure.

Muffler Installation

•

Scrape any carbon out of the expansion chamber.

•

Check the exhaust O-rings for s igns of damage.

If necessary, replace them with new ones.

•

Tighten:

Torque - Muffler Damper Mounting Bolts: 8.8 N·m (0.9

kgf·m, 78 in·lb)

Muffler Mounting Bolts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Muffler Baffle Change

•

Refer to the Exhaust System in the Periodic Maintenance

chapter.

ENGINE RIGHT SIDE 6-1

Engine Right Side

Table of Contents

Exploded View........................................................................................................................ 6-2

Specifications ......................................................................................................................... 6-6

Special Tools .......................................................................................................................... 6-7

Clutch Cable ........................................................................................................................... 6-8

Clutch Lever Free Play Check .......................................................................................... 6-8

Free Play Adjustment ........................................................................................................ 6-8

Clutch Cable Removal ...................................................................................................... 6-8

Clutch Cable Installation ................................................................................................... 6-8

Clutch Cable Lubrication and Inspection .......................................................................... 6-8

Clutch Cover........................................................................................................................... 6-9

Clutch Cover Removal ...................................................................................................... 6-9

Clutch Cover Installation ................................................................................................... 6-9

Right Engine Cover ................................................................................................................6-10

Right Engine Cover Removal............................................................................................ 6-10

Right Engine Cover Installation......................................................................................... 6-11

Right Engine Cover Disassembly ..................................................................................... 6-12

Exhaust Advancer Assembly Disassembly/Assembly ...................................................... 6-13

Right Engine Cover Assembly .......................................................................................... 6-13

Clutch ..................................................................................................................................... 6-15

Clutch Removal................................................................................................................. 6-15

Clutch Installation..............................................................................................................6-16

Friction and Steel Plates Wear, Damage Inspection......................................................... 6-17

Friction and Steel Plate Warp Inspection.......................................................................... 6-17

Spring Free Length Measurement .................................................................................... 6-18

Friction Plate/Clutch Housing Clearance .......................................................................... 6-18

Clutch Hub Spline Inspection............................................................................................ 6-18

Release Shaft Removal .................................................................................................... 6-18

Release Shaft Installation ................................................................................................. 6-19

External Shift Mechanism....................................................................................................... 6-20

External Shift Mechanism Removal .................................................................................. 6-20

External Shift Mechanism Installation ............................................................................... 6-20

External Shift Mechanism Inspection................................................................................ 6-21

Primary Gear .......................................................................................................................... 6-22

Primary Gear Removal ..................................................................................................... 6-22

Primary Gear Installation .................................................................................................. 6-22

Kickstarter............................................................................................................................... 6-23

Kickshaft Removal ............................................................................................................ 6-23

Kickstarter Assembly Disassembly/Assembly .................................................................. 6-23

Idle Gear Removal ............................................................................................................ 6-24

Idle Gear Installation ......................................................................................................... 6-24

6-2 ENGINE RIGHT SIDE

Exploded View

KX125:

ENGINE RIGHT SIDE 6-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Clutch Hub Nut 98 10.0 72

2 Clutch Spring Bolts 8.8 0.9 78 in·lb

3 Clutch Cover Bolts 8.8 0.9 78 in·lb

Governor Shaft Lever Positioning Plug

0.6 0.06 5in·lb

5 Oil Filler Cap 1.5 0.15 13 in·lb

6 Right Engine Cover Bolts 8.8 0.9 78 in·lb

7 Governor Shaft Lever Mounting Bolt 6.9 0.7 61 in·lb

8 Exhaust Valve Advancer Lever Mounting Allen Bolt 3.9 0.4 35 in·lb L

9 Primary Gear Nut 59 6.0 43

10 Gear Set Lever Nut 8.8 0.9 78 in·lb

11 Ratchet Plate Mounting Bolts 8.8 0.9 78 in·lb

12 Kick Ratchet Guide Bolt 8.8 0.9 78 in·lb

13 Kick Pedal Bolt 12 1.2 8.7

14 Shift Pedal Bolt 9.8 1.0 87 in·lb

15. Clutch Lever

16. Clutch Cable

17. Clutch Cover

18. Right Engine Cover

19. Governor Shaft Lever

20. Primary Gear

21. Exhaust Advancer Assembly

22. Gear Set Lever

23. Ratchet Assembly

24. Shift Shaft

25. Kickstarter Idle Gear

26. Ratchet Gear

27. Kick Gear

28. Kick Shaft

29. Clutch Hub

30. Release Lever Shaft

31. Push Rod

32. Steel Plate

33. Friction Plate

34. Sleeve

35. Clutch Housing

36. Push Rod Holder

37. Clutch Pressure Plate

EO: Apply engine oil.

G: Apply high temperature grease.

L: Apply a non-permanent locking agent to the threads.

M: Apply molybdenum disulfide g rease

O: Apply oil.

A: KX125-M1 ∼ M3 Model

B: KX125M6F Model ∼

6-4 ENGINE RIGHT SIDE

Exploded View

KX250:

ENGINE RIGHT SIDE 6-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Clutch Cover Bolts 8.8 0.9 78 in·lb

2 Right Engine Cover Bolts 8.8 0.9 78 in·lb

3 Oil Filler Cap 1.5 0.15 13 in·lb

Governor Shaft Lever Positioning Plug

0.6 0.06 5in·lb

5 Exhaust Valve Advancer Lever Mounting Allen Bolt 3.9 0.4 35 in·lb L

6 Gear Set Lever Nut 8.8 0.9 78 in·lb

7 Ratchet Plate Mounting Bolts 8.8 0.9 78 in·lb

8 Exhaust Shift Mechanism Return Spring Pin 42 4.3 31 L

9 Clutch Hub Nut 98 10.0 72

Clutch Spring Bolts

8.8 0.9 78 in·lb

11 Kick Ratchet Guide Bolt 8.8 0.9 78 in·lb

12 Kick Pedal Bolt 25 2.5 18

Shift Pedal Bolt

9.8 1.0 87 in·lb

14. Clutch Lever

15. Clutch Cable

16. Clutch Cover

17. Right Engine Cover

18. Governor Shaft Lever

19. Exhaust Advancer Assembly

20. Water Pump D river Gear

21. Primary Gear

22. Gear Set Lever

23. Ratchet Assembly

24. Shift Shaft

25. Ratchet Gear

26. Kickstarter Idle Gear

27. Kick Gear

28. Kick Shaft

29. Clutch Hub

30. Steel Plate

31. Friction Plate

32. Push Rod Holder

33. Clutch Pressure Plate

34. Clutch Housing

35. Sleeve

36. Push Rod

37. Release Lever Shaft

EO: Apply engine oil.

G: Apply high temperature grease.

L: Apply a non-permanent locking agent to the threads.

M: Apply m olybdenum disulfide grease.

O: Apply oil.

6-6 ENGINE RIGHT SIDE

Specifications

Item Standard Service Limit

Clutch

Lever Free Play 2 ∼ 3 mm (0.08 ∼ 0.12 in.) –––

Friction Plate Thickness

KX125 2.72 ∼ 2.88 mm (0.107 ∼ 0.113 in.) 2.6 mm (0.102 in.)

KX250 2.92 ∼ 3.08 mm (0.115 ∼ 0.121 in.) 2.8 mm (0.110 in.)

Steel Plate Thickness:

KX125 1.5 ∼ 1.7 mm (0.059 ∼ 0.067 in.) 1.4 mm (0.055 in.)

KX250

1.46 ∼ 1.74 mm (0.057 ∼ 0.069 in.) 1.36 mm (0.054 in.)

Friction Plate Warp 0.15 mm (0.006 in.) or less 0.3 mm (0.119 in.)

Steel Plate Warp 0.2 mm (0.008 in.) or less 0.3 mm (0.119 in.)

Clutch Spring Free Length:

KX125 46.8 mm (1.843 in.) 44.9 mm (1.768 in.)

KX250 35.0 mm (1.378 in.) 33.6 mm (1.323 in.)

Friction Plate/Clutch Housing

Clearance

KX125 0.04 ∼ 0.55 mm (0.0016 ∼ 0.0217 in.) 0.9 mm (0.0354 in.)

KX250

0.15 ∼ 0.45 mm (0.0059 ∼ 0.0177 in.) 0.8 mm (0.0315 in.)

ENGINE RIGHT SIDE 6-7

Special Tools

Clutch Holder:

57001-1243

Flywheel Holder:

57001-1313

Drum Pusher, 24:

57001-1440

Flywheel & Pulley Holder:

57001-1605

6-8 ENGINE RIGHT SIDE

Clutch Cable

Due to friction plate wear and clutch cable stretch over

a long period of use, the clutch must be adjusted in accor-

dance with the Periodic Maintenance Chart.

WARNING

To avoid a serious burn, never touch the hot engine

or exhaust chamber during clutch adjustment.

Clutch Lever Free Play Check

•

Refer to the Clutch Lever Free Play Check in the Periodic

Maintenance chapter.

Free Play Adjustment

•

Refer to the Clutch Lever Free Play Adjustment in the

Periodic Maintenance chapter.

Clutch Cable Removal

•

Slide the dust cover out of place.

•

Loosen the locknut at the upper of the cable, and turn the

adjusting nut to give the cable plenty of play.

•

Loosen the knurled locknut [A] at the clutch lever, and

screw in the adjuster [B].

•

Line up the slots [C] in the clutch lever, knurled locknut,

and adjuster, and then free the cable from the clutch lever.

○

For KX125, remove the magneto cover (see Release

Shaft Removal).

•

Free the clutch inner cable tip from the clutch release

lever.

CAUTION

Do not remove the clutch release shaft unless it is

absolutely necessary. If removed, release shaft oil

seal must be replaced with a new one.

•

Pull the clutch cable out of the frame.

Clutch Cable I nstallation

•

Run the clutch cable according to the Cable, Harness,

Hose Routing section of the Appendix chapter.

•

Adjusttheclutchcable(seeFreePlayAdjustment).

Clutch Cable Lubrication and Inspection

•

Lubricate the clutch cable using the pressure cable luber

in accordance with the Periodic M aintenance Chart.

•

With the cable disconnected at both ends, the cable

should move freely within the cable housing (see Appen-

dix chapter).

ENGINE RIGHT SIDE 6-9

Clutch Cover

Clutch Cover Removal

•

Drain the engine oil (see Engine Bottom End/Transmis-

sion chapter).

•

Remove the brake pedal (see Brake chapter).

•

Unbolt the clutch cover bolts [A], and take off the clutch

cover [B].

Clutch Cover I nstallation

•

There are two knock pins of the mating surfaces of right

engine cover and clutch cover.

•

Replace the clutch cover gasket with a new one.

•

Tighten the clutch cover bolts.

Torque - Clutch Cover Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)

•

Install the brake pedal (see Brake chapter)

6-10 ENGINE RIGHT SIDE

Right Engine Cover

Right Engine Cover Removal

•

Removal:

Engine Oil (drain) (see Engine Bottom End/Transmis-

sion chapter)

Coolant (drain) (see Cooling System chapter)

Cooling Hose Lower end

Kick Pedal

Brake Pedal

Muffler

•

Unscrew the KIPS cover bolt [A] and remove the KIPS

cover [B] from the right side of the c ylinder.

•

Remove the governor shaft lever in accordance with the

following procedure.

KX125

○

Remove the bolt [A] and pull out the governor shaft lever

[B] from the main shaft.

KX250

○

Remove the E-clip [A] from the operating rod.

○

Put a 9 mm (0.35 in.) spanner wrench [A] on the governor

shaft lever upper end.

○

Turn the governor shaft lever [B] counterclockwise with

the wrench, and take off the operating rod collar [C] by

pushing the operating rod into the cylinder.

○

Before pulling the governor shaft lever [A] free, turn the

remaining E-clip [B] to a suitable position as shown in the

figure to prevent the governor shaft l ever boss [C] and the

E-clip from hitting.

ENGINE RIGHT SIDE 6-11

Right Engine Cover

○

Remove the cover bolts [A] and take off the right engine

cover [B] and gasket.

Right Engine Cover Installation

•

There are two knock pins of the mating surfaces of the

crankcase and right engine cover.

•

In case the exhaust advancer assembly has been re-

moved, install it and turn the gear so as to level the gear

drive pin [A].

CAUTION

If the gear drive pin is not positioned level, it may

fall out when installing the right engine cover.

•

Apply a high-temperature grease to the kick pedal oil s eal

lips and kick shaft spline.

•

Tighten the right engine cover bolts and kick shaft mount-

ing bolt.

Torque - Right Engine Cover B olts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Kick Pedal Mounting Bolt:

KX125: 12 N·m (1.2 kgf·m, 8.7 ft·lb)

KX250: 25 N·m (2.5 kgf·m, 18 ft·lb)

KX125

•

Using the 14 mm (0.56 in.) spanner wrench [A], install the

governor shaft lever [B] as shown.

•

Tighten:

Torque - Governor Shaft Lever Mounting Bolt [C]: 6.9 N·m

(0.7 kgf·m, 61 in·lb)

•

Install the KIPS cover.

•

Tighten:

Torque - KIPS Cover Bolts:

KX125-M1: 4.9 N·m (0.5 kgf·m, 43 in·lb)

KX125-M2 ∼: 8.8 N·m (0.9 kgf·m, 78 in·lb )

KX250

•

Put a 9 mm (0.35 in.) spanner wrench [A] on the governor

shaft lever upper end.

•

Turn the governor shaft lever counterclockwise with the

wrench and fit the groove of the operating rod collar [B] to

the boss of the governor shaft lever, and install the collar

on the operating rod while turning the governor shaft lever

clockwise.

6-12 ENGINE RIGHT SIDE

Right Engine Cover

•

After installing the collar, install the E-clip [A] on the oper-

ating rod [B].

•

Tighten the KIPS cover bolts.

To rque - KIPS Cover Bolts: 2.5 N·m (0.25 kgf·m, 22 in·lb)

•

Apply grease to the inside of the brake pedal boss.

•

Tighten the brake pedal mounting bolt.

Torque - Brake Pedal Mounting Bolt: 25 N·m (2.5 kgf·m, 18

in·lb)

•

Fill the cooling system with coolant (see Cooling System

chapter).

•

Fill the transmission with engine oil (see Engine Bottom

End/Transmission chapter).

•

Check the rear brake.

Right Engine Cover Disassembly

•

Remove the right engine cover.

•

Turn the governor shaft lever [A] to the left, and remove

the exhaust advancer assembly [B].

•

Remove the Allen bolts [C], and take off the advancer

lever.

•

Pull the dust cover [D].

ENGINE RIGHT SIDE 6-13

Right Engine Cover

•

Remove the plug screw [A] and take out the governor

shaft lever positioning pin.

•

Pull the governor shaft lever [B] out of the right engine

cover.

•

Pull off the water pump s haft (see Cooling System chap-

ter).

Exhaust Advancer Assembly Disassembly/Assembly

•

The exhaust advancer assembly [A] consists of the fol-

lowing parts.

A. Pins

B. Rod

C. Guide

D. O-ring

E. Steel Balls

F. Holder

G. Needle Bearing

H. Spacer

I. Collar

J. Spring

K. Gear

•

Check the exhaust advancer assembly parts for damage.

Any damaged parts should be replaced with new ones.

•

When assembling, apply molybdenum disulfide grease

between the rod and inside/outside diameter parts of the

holder, needle bearing and spacer .

Right Engine Cover Assembly

•

Apply high temperature grease to the oil seal lips before

inserting the governor shaft lever.

•

Apply molybdenum disulfide grease to the surface of the

lever s haft, and insert the governor shaft lever [A] into the

right engine cover hole.

•

Insert the positioning pin [B] into the hole then fit it to the

grove [C] of the shaft.

•

Tighten the governor shaft lever positioning plug screw

[D] securely.

Torque - Governor Shaft Lever Positioning Plug: 0.6 N·m

(0.06 k gf·m, 5 in·lb)

•

Install the dust cover.

6-14 ENGINE RIGHT SIDE

Right Engine Cover

•

Apply a non-permanent locking agent to the threads of

the advancer mounting

Allen bolts.

•

Tighten the advancer lever mounting Allen bolts [A].

Torque - Advancer Lever Mounting Allen Bolts: 3.9 N·m

(0.4 kgf·m, 35 in·lb)

•

Fit the advancer lever pin [B] into the groove [C] on the

exhaust advancer assembly [D], and install the assembly

in the engine cover while turning the governor shaft lever

to the left.

ENGINE RIGHT SIDE 6-15

Clutch

Clutch Removal

•

Remove the clutch c over (see Clutch Cover Removal).

•

Remove the c lutch spring bolts [A], spring, and clutch

pressure plate [B].

•

Remove the push rod holder assembly [A], friction plates,

steel plates, and push rod [B].

•

For KX125, Remove steel boll [C].

•

Remove the clutch hub nut [A] and washer.

NOTE

○

Use the clutch holder [B] to prevent the clutch hub from

rotating.

Special Tool - Clutch Holder: 57001-1243

•

Remove the clutch hub and housing, needle bearing [A],

and sleeve [B].

6-16 ENGINE RIGHT SIDE

Clutch

Clutch Installation

•

Apply molybdenum disulfide grease to the outside of the

sleeve.

•

Apply engine oil to the inside of the clutch housing gear

and kickstarter driven gear.

•

Install the sleeve, needle bearing, clutch hub and hous-

ing.

○

Do not forget to install the thrust washer [A] before in-

stalling the clutch hub [B].

•

Tighten the c lutch hub nut [A].

Torque - Clutch H ub Nut: 98 N·m (10 kgf·m, 72 ft·lb)

NOTE

○

Use the clutch holder [B] to prevent the clutch hub from

rotating.

Special Tool - Clutch Holder: 57001-1243

•

For KX250, stake the clutch hub nut [A] in three points [B]

to the spline grooves to secure it in place.

CAUTION

When staking the nut, be careful not to apply shock

to the shaft and bearings. Such a shock could dam-

age the shaft and/or bearings.

•

Install the friction plates and steel plates, starting with a

friction plate and alternating them. Finishing with a friction

plate.

CAUTION

If dry steel plates and friction plates are installed,

apply transmission oil to the surfaces of each plate

to avoid clutch plate seizure.

•

For KX125, the grooves [A] on the friction plate surfaces

are cut tangentially and radially, install the first and last

friction plates [B] so that the grooves run toward the cen-

ter in the direction of the clutch housing rotation (counter-

clockwise viewed from the engine right side).

•

Apply molybdenum disulfide grease to the rubbing portion

of the push rod holder.

•

Tighten the clutch spring bolts fixing the flywheel with the

special tool.

To rque - Clutch Spring Bolts: 8.8 N·m (0.9 kgf·m, 78 i n·lb)

Special Tool - Flywheel Holder: 57001-1313

ENGINE RIGHT SIDE 6-17

Clutch

•

For KX125; check the release shaft lever positions [A].

○

Remove the magneto cover.

○

Pushing the release shaft lever [C] lightly upward m ea-

sure the distance between the release shaft lever and

clutch cable set position of crankcase [D].

View [E]

Release Shaft Lever Position

Standard:

46.9 ∼ 53.9 mm (1.85 ∼ 2.12 in.)(KX125-M1)

49.0 ∼ 55.6 mm (1.93 ∼ 2.19 in.)(KX125-M2 ∼)

If the lever position is not within the standard, select the

correct thickness of adjusting washer(s) [B] according to

the tables shown.

Adjusting Washers

Thickness Part NUMB ER

1.5 mm (0.06 in.)

92200-1548

1.0 mm (0.04 in.)

92200-0045

Release Shaft Lever Position and Adjusting Washer Se-

lection

(KX125-M1)

Position Distance Washer Thickness

Qty

46.9 mm to 53.9 mm (1.85 ∼ 2.12

in.) (Standard)

1.5 mm (0.06 in.)

More than 53.9 mm (2.12 in.) 1.0 mm (0.04 in.)

Less than 46.9 mm (1.85 in.) 1.0 mm (0.04 in.)

(KX125-M2 ∼)

Position Distance Washer Thickness

Qty

49.0 m m to 55.6 mm (1.93 ∼ 2.19

in.) (Standard)

1.5 mm (0.06 in.)

More than 55.6 mm (2.19 in.) 1.0 mm (0.04 in.)

Less than 49.0 mm (1.93 in.) 1.0 mm (0.04 in.)

Remove the push rod holder assembly as necessary and

reinstall the clutch.

○

Install the magneto cover.

Friction and Steel Plates Wear, Damage Inspection

•

Refer to the Friction and Steel Plates Wear, Damage In-

spection in the Periodic Maintenance chapter.

Friction and Steel Plate Warp Inspection

•

Refer to the Friction and Steel Plate Wrap Inspection in

the Periodic Maintenance chapter.

6-18 ENGINE RIGHT SIDE

Clutch

Spring F ree Length M easurement

•

Since the spring [A] becomes shorter as it weakens,

check its free length to determine its condition.

If any of the springs is shorter than the service limit, it must

be replaced.

Clutch Spring Free Length

KX125

Standard: 46.8 mm (1.843 in.)

Service Limit: 44.9 mm (1.768 in.)

KX250

Standard: 35 mm (1.378 in.)

Service Limit: 33.6 mm (1.323 in.)

Friction Plate/Clutch Housing Clearance

•

Measure the clearance between the tangs [A] on the fric-

tion plate and the fingers [B] of the clutch housing.

If this clearance is excessive, t he clutch will be noisy.

If the clearance exceeds the service limit, replace the fric-

tion plates.

Friction Plate/Clutch Housing Clearance

KX125:

Standard: 0.04 ∼ 0.55 mm (0.0016 ∼ 0.0217 in.)

Service Limit: 0.9 mm (0.0354 in.)

KX250:

Standard: 0.15 ∼ 0.45 mm (0.0059 ∼ 0.0177 in.)

Service Limit: 0.8 mm (0.0315 in.)

Clutch Hub Spline Inspection

•

Visually inspect where the teeth on the steel plates wear

against the splines [A] of the clutch hub.

If there are notches worn into the splines, replace the

clutch hub. Also, replace the clutch plates if their teeth

are damaged.

Release Shaft Removal

•

Remove the clutch (see Clutch Removal).

•

Remove the clutch cable upper end (see Clutch Cable

Removal).

○

For KX125; remove the magneto cover.

•

Remove the tips [A] of the clutch cable.

•

Pull the lever and shaft assembly [B] out of the crankcase.

ENGINE RIGHT SIDE 6-19

Clutch

Release Shaft Installation

•

Apply high temperature grease to the oil seal lips.

•

Apply engine oil to the bearing in the hole of the

crankcase.

•

Insert the release shaft straight in to the hole of the

crankcase.

•

Install the clutch (see Clutch Installation).

○

For KX125; install the magneto cover.

6-20 ENGINE RIGHT SIDE

External Shift Mechanism

External Shift Mechanism Removal

•

Remove:

Shift Pedal

Right Engine Cover (see Right Engine Cover Removal)

Clutch (see Clutch Removal)

•

Pull out the external shift shaft [A].

•

Remove the bolts [B] and take off the shift ratchet assem-

bly [ C] with collar.

•

Remove the nut [D], and take off the gear set lever [E].

External Shift Mechanism Installation

•

Install the gear set l ever.

○

Do not forget to install the color.

•

Tighten the gear set lever nut.

Torque - Gear Set Lever Nut: 8.8 N·m (0.9 kgf·m, 78 in·lb)

•

Set up the shift ratchet assembly as shown in the figure.

Ratchet [A]

Pawls [B]

Pins [C]

Springs [D]

•

Then install the ratchet assembly [A] to the ratchet plat [B]

as shown in the figure.

•

Install the ratchet assembly to the shift drum.

•

Tighten:

Torque - Ratchet Plat Mounting B olts: 8.8 N·m (0.9 kgf·m,

78 in·lb)

•

Before installing the shift shaft, apply high temperature

grease to the oil seal lips and shift shaft splines.

•

Install the shift shaft.

○

Do not forget to install the collar [A].

•

Instal:

Clutch (see Clutch Installation)

Right Engine Cover (see Right Engine Cover Installa-

tion)

ENGINE RIGHT SIDE 6-21

External Shift Mechanism

•

Instal the shift pedal [A] as shown.

0 ∼ 20 mm (0 ∼ 0.79 in.) [B]

•

Tighten:

Torque - Shift Pedal Bolt: 9.8 N·m (1.0 kgf·m, 87 in·lb)

External Shift Mechanism Inspection

•

Check the shift shaft [A] for bending or damage to the

splines.

If the shaft is bent, straighten or replace it. If the splines

are damaged, replace the shift mechanism.

•

Check the return spring [B] for cracks or distortion.

If the spring is damaged in any way, replace it.

•

Check the shift mechanism arm [C] for distortion.

If the shift mechanism arm is damaged in any way, re-

place the shift m echanism.

•

Check the collar [D] for damage.

If the collar is damaged in any way, replace it.

•

Check the ratchet assembly for damage.

If ratchet, pawls, pins or springs are damaged in any way,

replace them.

•

For KX250, Check that the return s pring pin [A] is not

loose.

If it is loose, unscrew it, apply a non-permanent locking

agent to the threads, and tighten it.

Torque - Return Spring Pin: 42 N·m (4.3 kgf·m, 31 ft·lb)

•

Check the gear set lever and its spring for cracks or dis-

tortion.

If the lever or spring is damaged in any w ay, replace them.

•

Visually inspect the shift drum cam.

If it is badly worn or if it shows any damage, replace it.

6-22 ENGINE RIGHT SIDE

Primary Gear

Primary Gear Removal

•

Remove the right engine cover (see Right Engine Cover

Removal)

•

Remove the clutch (see Clutch Removal).

•

For KX125, remove the primary gear nut [A], spring

washer, woodruff key, primary gear [B], and O-ring.

NOTE

○

Use the flywheel & pulley holder to prevent the crank-

shaft from the rotating.

Special Tool - Flywheel & Pulley Holder: 57001-1605

•

For KX250, remove the circlip [A], and take off the water

pump drive gear [B] and primary gear [C].

Special Toos - Outside Circlip Pliers: 570 01 -144

Primary Gear Installation

KX125

•

Instal the O-ring.

•

Fit the woodruff key [B] on the crankshaft groove.

•

Install the spring washer so that concave side faces [A]

inward.

•

Tighten the primary gear nut.

Torque - Primary Gear Nut: 59 N·m (6.0 kgf·m, 43 ft·lb)

NOTE

○

Use the flywheel & pulley holder to prevent the crank-

shaft from the rotating.

Special Toos - Flywheel & Pulley Holder: 57001-1605

KX250

•

Install the primary gear [A] so that chamfered side [B]

faces outward.

•

Install the water pump drive gear [C] so that the cham-

feredside[D]facesoutward.

•

Replace the old circlip with a new one.

Special Toos - Outside Circlip Pliers: 570 01 -144

ENGINE RIGHT SIDE 6-23

Kickstarter

Kickshaft Removal

•

Remove:

Right Engine Cover

Clutch Housing

•

Pull the end of the kick spring [A] out of the hole in the

crankcase.

•

Remove the kickstarter assembly [B].

•

Remove the bolts [A], take off the ratchet guide [B].

Kickstarter Assembly Disassembly/Assembly

•

The kickstarter assembly consists of the following parts.

•

Check the kickstarter assembly parts for damage. Any

damaged parts should be replaced with new ones.

A. Idle Gear

B. Circlip

C. Washer

D. Spring

E. Ratchet Gear

F. Kick Gear

G. Kick Shaft

H. K ick Spring

I. Spring Guide

•

Apply molybdenum disulfide grease to the inside of the

kick gear and ratchet gear.

•

When assembling the ratchet gear [A] onto the kick shaft

[B], align the punch mark [C] on the ratchet gear with the

punch mark [C] on the kick shaft.

•

Replace the circlips that were removed with new ones.

Special Tool - Outside Circlip Pliers: 57001-144

6-24 ENGINE RIGHT SIDE

Kickstarter

Idle Gear Removal

•

Remove:

Right Engine Cover (see Right Engine Cover Removal)

Clutch Housing (see Clutch Removal)

•

For KX125, pull off the idle gear.

•

For KX250, remove the circlip [A] and pull off the idle gear

[B].

Special Tool - Out side Circ lip Pliers : 57 0 01 - 144

Idle Gear Installation

•

Apply molybdenum disulfide grease to the inside of the

idle gear.

•

Replace the circlip with a new one.

Special Tool - Out side Circ lip Pliers : 57 0 01 - 144

ENGINE REMOVAL/INSTALLATION 7-1

Engine Removal/Installation

Table of Contents

Exploded View........................................................................................................................ 7-2

Special Tool ............................................................................................................................ 7-4

Engine Removal/Installation ................................................................................................... 7-5

Engine Removal................................................................................................................ 7-5

Engine Installation............................................................................................................. 7-6

7-2 ENGINE REMOVAL/INSTALLATION

Exploded View

ENGINE REM OVAL/INSTALLATION 7-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

Engine Mounting Nuts:

KX125/250-M1 44 4.5 331

KX125/250-M2 ∼ 49 5.0 36

Engine Mounting Bracket Nut (Engine Side 10 mm):

KX125/250-M1 44 4.5 332

KX125/250-M2 ∼ 49 5.0 36

Engine Mounting Bracket Nuts (Frame Side 8 mm)

29 3.0 22

4 Swing Arm Pivot Shaft Nut 98 10.0 72

5. Frame

6. Engine Mounting Bracket

7. Pivot Shaft

8. Swingarm

G: Apply grease.

7-4 ENGINE REMOVAL/INSTALLATION

Special Tool

Jack:

57001-1238

ENGINE REM OVAL/INSTALLATION 7-5

Engine Removal/Installation

Engine Removal

•

Drain the engine oil (see Engine Bottom End/Transmis-

sion chapter).

•

Drain the coolant (see Cooling System chapter).

•

Remove:

Radiator Shrouds

Side Covers

Seat

Fuel Tank

Cooling Hoses

Radiators

Expansion Chamber

Ignition Coil (KX250)

Spark Plug Cap

Carburetor (with Cables and Hoses)

Clutch Cable Lower End

Drive Chain

Engine Sprocket

Shift Pedal

Brake P edal

•

Disconnect the magneto output lead, and free the leads

from the clamp at the left side of the cylinder.

•

Unbolt the mounting bolts [A] and remove the engine

mounting brackets [B].

•

Place a jack [A] under the frame to lift the motorcycle off

the ground, and put blocks under the front and rear tires

to steady the motorcycle.

WARNING

The swingarm pivot shaft also serves as the en-

gine mounting bolt. Take precautions to insure the

frame is well supported, and that the motorcycle

will not fall over when the pivot shaft is removed.

Special Tool - Jack: 57001-1238

•

Remove the engine mounting bolts [B].

•

Pull out the swing arm pivot shaft [C].

•

Lift the engine out to the right.

7-6 ENGINE REMOVAL/INSTALLATION

Engine Removal/Installation

Engine Installation

•

Tighten the following nuts.

Torque - Engine Mounting Nuts:

44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250-M1)

49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250-M2∼)

Engine Mounting Bracket Nuts 10 mm:

44 N·m (4.5 kgf·m, 33 ft·lb) (KX125/250-M1)

49 N·m (5.0 kgf·m, 36 ft·lb) (KX125/250-M2∼)

Engine Mounting Bracket Nuts 8 mm :

29 N·m (3.0 kgf·m, 22 ft·lb)

Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

•

To route the leads, cables and hoses, refer to the Appen-

dix chapter.

•

To install parts removed, refer to the appropriate chapters.

•

Fill the cooling system with coolant (see Cooling System

chapter).

•

Fill the transmission with engine oil (see Engine Bottom

End/Transmission chapter).

•

Adjust:

Throttle Cable

Clutch Cable

Drive Chain

Rear Brake

ENGINE BOTTOM END/TRANSMISSION 8-1

Engine Bottom End/Transmission

Table of Contents

Exploded View........................................................................................................................ 8-2

Specifications ......................................................................................................................... 8-6

Special Tools and Sealant ...................................................................................................... 8-7

Transmission Oil..................................................................................................................... 8-8

Oil Level Inspection........................................................................................................... 8-8

Oil Change ........................................................................................................................ 8-8

Crankcase .............................................................................................................................. 8-9

Crankcase Splitting ........................................................................................................... 8-9

Crankcase Disassembly ................................................................................................... 8-10

Crankcase Assembly ........................................................................................................ 8-10

Crankshaft, Connecting Rod .................................................................................................. 8-13

Crankshaft Removal ......................................................................................................... 8-13

Crankshaft Installation ...................................................................................................... 8-13

Crankshaft Disassembly ................................................................................................... 8-13

Crankshaft Assembly ........................................................................................................ 8-13

Connecting Rod Big End Radial Clearance ...................................................................... 8-14

Connecting Rod Big End Seizure ..................................................................................... 8-14

Connecting Rod Big End Side Clearance ......................................................................... 8-14

Crankshaft Runout ............................................................................................................ 8-14

Crankshaft Alignment........................................................................................................ 8-15

Transmission .......................................................................................................................... 8-16

Transmission Shaft Removal ............................................................................................ 8-16

Transmission Shaft Installation ......................................................................................... 8-16

Transmission Shaft Disassembly...................................................................................... 8-16

Transmission Shaft Assembly........................................................................................... 8-16

Shift Drum and Fork Installation ........................................................................................ 8-18

Shift Fork Bending ............................................................................................................ 8-19

Shift Fork/Gear Groove Wear ........................................................................................... 8-19

Shift Fork Guide Pin/Shift Drum Groove Wear ................................................................. 8-19

Gear Damage ................................................................................................................... 8-20

Gear Dog/Gear Dog Hole Damage................................................................................... 8-20

Ball Bearing Wear ............................................................................................................. 8-20

8-2 ENGINE BOTTOM END/TRANSMISSION

Exploded View

KX125:

ENGINE BOTTOM END/TRANSMISSION 8-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Output Shaft Bearing Retaining Screws 5.4 0.55 48 in·lb L

Shift Drum Bearing Retaining Screws (KX125-M1) 6.4 0.65 56 in·lb L

Shift D rum Bearing Retaining Bolts (KX125-M2 ∼) 8.8 0.9 78 in·lb L

Engine Oil Drain Plug

20 2.0 14.5

4 Crankcase Bolts 8.8 0.9 78 in·lb

5 Flywheel Bolt 22 2.2 16

Shift Drum Operating Cam Bolt

24 2.4 17

7. Left Crankcase

8. Right Crankcase

9. Crankshaft Assembly

10. Flywheel Magneto

11. Stator

12. Drive Shaft

13. Output Shaft

14. Engine Sprocket

15. Shift Fork

16. Shift Rod

17. Shift Drum

18. Shift Drum Operating Cam

19. Shift Pedal

20. Shift Shaft

A: KX125M6F Model ∼

EO: Apply engine oil to the transmission gears and shift forks, etc.

G: Apply high temperature grease.

L: Apply a non-permanent locking agent.

LG: Apply liquid gasket to the left and right case mating surface.

O: Apply 2-stroke engine oil.

R: Replacement parts

8-4 ENGINE BOTTOM END/TRANSMISSION

Exploded View

KX250:

ENGINE BOTTOM END/TRANSMISSION 8-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Crankcase Bolts 8.8 0.9 78 in·lb

2 Output Shaft Bearing Retaining Screws 5.4 0.55 48 in·lb L

3 Shift Drum Bearing Retaining Bolts 8.8 0.9 78 in·lb

Engine Oil Drain Plug

20 2.0 14.5

5 Drive Shaft Bearing Retaining Bolts 8.8 0.9 78 in·lb

6 Flywheel Nut 78 8.0 58

Shift Drum Operating Cam Bolt

24 2.4 17 L

8. Left Crankcase

9. Right Crankcase

10. Crankshaft Assembly

11. Stator

12. Flywheel Magneto

13. Drive Shaft

14. Output Shaft

15. Engine Sprocket

16. Shift Fork

17. Shift Rod

18. Shift Drum Operating Cam

19. Shift Drum

20. Shift Pedal

21. Shift Shaft

EO: Apply engine oil to the transmission gears and shift forks, etc.

G: Apply high temperature grease.

L: Apply a non-permanent locking agent.

LG: Apply liquid gasket to the left and right case mating surface.

O: Apply 2-stroke engine oil.

R: Replacement parts.

8-6 ENGINE BOTTOM END/TRANSMISSION

Specifications

Standard

Item

KX125/250-M1

Service Limit

Transmission Oil

Grade API SE, SF or SG –––

API SH, SJ or SL with JASO MA

Viscosity

SAE 10W-40

–––

Capacity:

KX125 0.7 L (0.74 US qt) –––

KX250 0.85 L (0.90 US qt) –––

Crankshaft, Connecting Rod

Connecting Rod Bend 0.03 mm (0.0012 in.)/100 mm (3.937 in.)

or less

0.2 mm (0.008 in.)/100

mm (3.937 in.)

Connecting Rod Big End

Radial Clearance:

KX125 0.036 ∼ 0.047 mm (0.0014 ∼ 0.0019 in.) 0.10 mm (0.004 in.)

KX250 0.037 ∼ 0.049 mm (0.0015 ∼ 0.0019 in.) 0.10 mm (0.004 in.)

Connecting Rod Big End Side

Clearance:

KX125 0.40 ∼ 0.50 mm (0.0157 ∼ 0.0197 in.) 0.70 mm (0.028 in.)

KX250 0.45 ∼ 0.55 mm (0.0177 ∼ 0.0217 in.) 0.70 mm (0.028 in.)

Crankshaft Runout 0.03 mm (0.0012 in.) or less 0.05 mm (0.002 in.)

Transmission

Gear Backlash: 0.02 ∼ 0.20 mm (0.0008 ∼ 0.0078 in.) 0.30 mm (0.012 in.)

Shift Fork Ear Thickness:

KX125 4.90 ∼ 5.00 mm (0.1768 ∼ 0.1969 in.) 4.80 mm (0.189 in.)

KX250 4.40 ∼ 4.50 mm (0.1732 ∼ 0.1772 in.) 4.30 mm (0.169 in.)

Gear Shift Fork Groove Width:

KX125 5.05 ∼ 5.15 mm (0.1988 ∼ 0.2028 in.) 5.25 mm (0.207 in.)

KX250 4.55 ∼ 4.65 mm (0.1791 ∼ 0.1830 in.) 4.75 mm (0.187 in.)

Shift Fork Guide Pin Diameter 5.90 ∼ 6.00 mm (0.2323 ∼ 0.2362 in.) 5.80 mm (0.228 in.)

Shift Drum Groove Width 6.05 ∼ 6.20 mm (0.2382 ∼ 0.2440 in.) 6.25 mm (0.246 in.)

ENGINE BOTTOM END/TRANSMISSION 8-7

Special Tools and Sealant

Bearing Puller Adapter:

57001-136

Outside Circlip Pliers:

57001-144

Bearing Puller:

57001-158

Crankcase Splitting Tool Assembly:

57001-1098

Bearing Driver Set:

57001-1129

Crankshaft Jig:

57001-1174

Kawasaki Bond (Liquid Gasket - Silver):

92104-002

8-8 ENGINE BOTTOM END/TRANSMISSION

Transmissio n Oil

In order for the transmission and clutch to function prop-

erly, always maintain the transmission oil at the proper level

and change the oil periodically.

WARNING

Motorcycle operation with insufficient, deteri-

orated, or contaminated transmission oil will

accelerated wear and may result in transmission

seizure, and injury.

Oil Level Inspection

•

Refer to the Transmission Oil Level Inspection in the Pe-

riodic Maintenance chapter.

Oil Change

•

Refer to the Transmission Oil C hange in the Periodic

Maintenance chapter.

ENGINE BOTTOM END/TRANSMISSION 8-9

Crankcase

Crankcase Splitting

•

Remove the engine (see the Engine Removal/Installation

chapter).

•

Set the engine on a clean surface while parts are being

removed.

•

Remove:

Magneto Cover

Cylinder Head (see Engine Top End chapter)

Cylinder (see Engine Top End chapter)

Piston (see Engine Top End chapter)

Right Engine Cover (see Engine Right Side chapter)

Clutch (see Engine Right Side chapter)

Primary Gear (see Engine Right Side chapter)

Kickstarter Assembly (see Engine Right Side chapter)

Kickstarter Idle Gear (see Engine Right Side chapter)

External Shift Mechanism (see Engine Right Side chap-

ter)

Shift Ratchet Assembly (see Engine Right Side chapter)

Gear Set Lever [A]

Shift Drum Operating Cam [B]

Output Shaft Sleeve [C] and O-ring [D] (KX250, O-rings)

Flywheel Magneto and Stator (see Electrical System

chapter)

Reed Valve (KX125) (see Fuel System chapter)

•

Remove the crankcase bolts [A].

•

Install the crankcase splitting tool [A] and bearing puller

adapter [B] into the left side of the crankcase. Be certain

to screw the tool in all the way.

Special Tools - Crankcase Splitting Tool Assembly: 57001

-1098

Bearing Puller Adapter: 57001-136

•

Tighten the bolt on the crankcase splitting tool to split t he

crankcase halves.

•

Once the crankcase is split, remove the crankcase split-

ting tool, and lift off the left crankcase half.

8-10 ENGINE BOTTOM END/TRANSMISSION

Crankcase

•

Pull out the shift rods [A].

•

Disengage the shift fork guide pins from the shift drum

grooves.

•

Take off the shift drum [B]

•

Remove the shift forks [C] from the transmission gears.

•

Take out the drive shaft [D] and output shaft [E] together

with their gear meshed.

•

Remove the crankshaft from the right crankcase half us-

ingapress.

Crankcase Disassembly

CAUTION

Do not remove the bearings and the oil seals unless

it is necessary.

Removal may damage them.

Crankcase Assembly

•

Before fitting the left case on the right case, note the fol-

lowing:

○

Chip off the old gasket from the mating surfaces of the

crankcase halves, and clean off the crankcase with a high

-flash point solvent. After cleaning, apply engine oil to the

transmission gears, shift drum, shift forks and so on.

○

Be sure to replace any oil seal removed with a new one.

Press in the new oil seal using a press and suitable tools

so that the seal surface is flush with the surface of the

crankcase.

○

Apply high temperature grease to the oil seal lips.

○

Press in the ball bearings using the bearing driver set until

the bearing is bottomed.

Special Tool - Bearin g Driver Set: 57001-1129

○

Install the bearing for the output shaft into the left

crankcase half so that stepped side faces [A] inside.

CAUTION

Install the bearings for the crankshaft in the right

and left crankcase so that their sealed sides face

toward the oil seal side.

○

Tighten the output and drive shaft bearing retaining

bolts/screws securely.

Torque - Bearing Retaining Bolts: 8.8 N·m (0.9 kgf·m, 78

in·lb)

Bearing Retaining Screws: 5.4 N·m (0.55 kgf·m, 48

in·lb)

ENGINE BOTTOM END/TRANSMISSION 8-11

Crankcase

○

For KX125M; install the release shaft needle bearing as

shown.

[A] Oil Seal

[B] Needle Bearing

[C] Needle Bearing Position

KX125-M1 ∼ M2: 3.5 ±0 .2 mm (0.138 ±0.008 in.)

KX125-M3 ∼: 3 .3 ±0.2 mm (0.130 ±0.008 in.)

○

If the crankshaft bearings stay on the crankshaft when

splitting the crankcase, remove the bearings from the

crankshaft and reinstall them in the crankcase, and then

assemble the crankcase (see Crankshaft Removal and

Installation).

•

Turn the crankshaft [A] to BDC, and install the crankshaft

jig [C] between the flywheels opposite the connecting rod

[B] big end to protect flywheel alignment as shown.

○

If the crankshaft has been removed from the crankcase,

install the jig between the crankshaft flywheels before

pressing the crankshaft into the right crankcase half.

Special Tool - Crankshaft Jig: 57001-1174

•

Install the transmission shaft as a set (see this chapter).

•

Install the shift fork, shift drum and shift rod.

•

Check to see that the crankcase knock pins [A] and O-ring

[B] (KX125) are in place on the right crankcase half. If any

of them has been removed, replace it with a new one.

8-12 ENGINE BOTTOM END/TRANSMISSION

Crankcase

•

Apply liquid gasket to the mating surface [A] of the

crankcase half.

Sealant - Kawasaki Bond (Liquid Gasket - Silver): 92104

-002

•

Using a suitable tool on the left crankcase to press [A]

around the hole for the crankshaft, fit the crankcase

halves together with a press on the tool.

NOTE

○

Constantly check the alignment of the two crankcase

halves, and the position of the transmission shafts, and

shift drum. The front and rear of the crankcase must be

pushed together evenly.

•

Remove the crankshaft jig from the flywheels.

•

Tighten the crankcase bolts starting with the ones around

the crankshaft, and then the farther ones.

○

At this time, tighten the crankcase bolt [A] and clamp [B]

for the breather hoses together.

Torque - Crankcase Bolts: 8.8 N·m (0.9 kgf·m, 78 in·lb)

•

Check to see that the crankshaft, drive shaft, and output

shaft all turn freely (in the neutral position).

If the crankshaft will not turn, probably the crankshaft is

not centered; tap the appropriate end of the crankshaft

with a mallet to reposition it.

•

Spinning the output shaft, shift the transmission through

all the gears to make certain there is no binding and that

all the gears shift properly.

•

Install the parts removed in the reverse order of removal,

and refer to the appropriate chapters.

○

Replace the O-ring on the output shaft with a new one.

ENGINE BOTTOM END/TRANSMISSION 8-13

Crankshaft, Connecting Rod

Crankshaft Removal

•

Split the crankcase (see Crankcase Splitting).

•

Remove the transmission shafts (see Transmission Shaft

Removal).

•

Using a press, remove the crankshaft from the right

crankcase.

○

If the bearings stay on the crankshaft when splitting the

crankcase or removing the crankshaft from the right

crankcase, remove the bearings from the crankshaft with

a bearing puller [A] and adapter [B].

Special Tools - Bearing Puller: 57001-158

Bearing Puller Adapter: 57001-136

Crankshaft Installation

•

When installing the crankshaft bearings [B], apply high

temperature grease to the outer sides of the bearings,

and then press them into the c rankcase using the bearing

driver [A] until the bearing bottoms against the step.

○

Position the crankcase half so that the main bearing hous-

ing is seated on a suitable press fixture.

○

Install the crankshaft bearing so that the mark side faces

out.

Special Tool - Bearing Driver Set: 57001-1129

•

Insert the crankshaft jig [C] between the crankshaft fly-

wheels opposite the connecting rod [B] big end to protect

flywheel alignment as shown, and press the crankshaft

[A] into the right crankcase.

○

When pressing, position the jig in the crankcase opening

so the jig does not hit the crankcase.

Special Tool - Crankshaft Jig: 57001-1174

•

Apply 2-stroke oil to the connecting rod big end bearing.

Crankshaft Disassembly

Since assembly of the crankshaft demands exacting tol-

erances, the disassembly and reassembly of the crankshaft

can only be done by a shop having the necessary tools and

equipment.

•

If it should be necessary to disassemble the crankshaft,

use a press to remove the crankpin.

Crankshaft Assembly

Since the assembly of the crankshaft demands exacting

tolerances, the disassembly and reassembly of the c rank-

shaft can only be done by a shop having the necessary tools

and equipment.

•

Reassemble the crankshaft according to the standard tol-

erances in Specifications.

○

Connecting rod bend, twist

○

Connecting rod big end radial clearance.

○

Cold-fitting tolerance between crankpin and flywheels.

○

Side clearance between the connecting rod big end and

one of flywheels.

○

Crankshaft runout.

8-14 ENGINE BOTTOM END/TRANSMISSION

Crankshaft, Connecting Rod

Connecting Rod Big End Radial Cleara nce

•

Set the crankshaft in a flywheel alignment jig or on V

blocks, and place a d ial gauge against the connecting rod

big end.

•

Push the connecting rod first towards the gauge and then

in the opposite direction. The difference between the two

gauge readings is the radial clearance.

Connecting Rod Big End Radial Clearance

Standard:

KX125 : 0.036 ∼ 0.047 mm (0.0014 ∼ 0.0019 in.)

KX250 : 0.037 ∼ 0.049 mm (0.0015 ∼ 0.0019 in.)

Service Limit :

KX125: 0.10 mm (0.004 in.)

KX250: 0.10 mm (0.004 in.)

If the radial clearance exceeds the service limit, the crank-

shaft should be either replaced or disassembled and the

crankpin, needle bearing, and connecting rod big end ex-

amined for wear.

Connecting Rod Big End Seizure

In case of serious seizure with damaged flywheels, the

crankshaft must be replaced.

In case of less serious damage, disassemble the crank-

shaft and replace the crankpin, needle bearing, side

washers, and connecting rod.

Connecting Rod Big End Side Clearance

•

Measure the side clearance [A] of the connecting rod with

a thickness gauge.

Connecting Rod Big End Side Clearance

Standard:

KX125:

0.40 ∼ 0.50 mm (0.0157 ∼ 0.0197 in.)

KX250:

0.45 ∼ 0.55 mm (0.0177 ∼ 0.0217 in.)

Service Limit: 0.70 mm (0.028 in.)

If the clearance exceeds the service limit, replace the

crankshaft.

Crankshaft Runout

•

Set the crankshaft in a flywheel alignment jig or on V

blocks, and place a dial gauge against the points indi-

cated.

•

Turn the crankshaft slowly. The maximum difference in

gauge readings is the crankshaft runout.

(A): KX125 - 8.0 mm (0.315 in.)

KX250 - 8.5 mm (0.335 in.)

Crankshaft Runout

Standard: 0.03 mm (0.0012 in.) or less

Service Lim it: 0.0 5 mm (0.002 in.)

If the runout at either point exceeds the service limit, align

the flywheels so that the runout falls within the service

limit.

ENGINE BOTTOM END/TRANSMISSION 8-15

Crankshaft, Connecting Rod

Crankshaft Alignment

•

In the case of horizontal misalignment, which is the most

common, strike the projecting rim of the flywheel with a

plastic, soft lead, or brass hammer as indicated in the

figure.

•

Recheck the runout with a dial gauge, repeating the

process until the runout falls within the service limit.

○

Vertical misalignment is corrected either by driving a

wedge in between the flywheels or by squeezing the

flywheel rims in a vise, depending on the nature of the

misalignment. In cases of both horizontal and vertical

misalignment, c orrect the horizontal misalignment first.

CAUTION

Don’t hammer the flywheel at point "A".

If flywheel misalignment cannot be corrected by the above

method, replace the crankpin or the crankshaft itself.

8-16 ENGINE BOTTOM END/TRANSMISSION

Transmissio n

Transmission Shaft Removal

•

Split the crankcase (see Crankcase Splitting).

•

Pull off the shift rods [A], and disengage the shift fork

guide pins from the shift drum grooves.

•

Remove the shift drum [B].

•

Remove the shift forks [C] from the transmission gears.

•

Take out the drive shaft [D] and output shaft [E] together,

with their gears meshed.

Transmission Shaft Installation

•

Hold the drive shaft [A] and output shaft [B] together, with

their gears meshed, and fit them into the right crankcase

half.

•

To install the shift forks and shift drum (see Shift Drum

and Fork Installation).

Transmission Shaft Disassembly

•

Remove the transmission shafts (see Shaft Removal).

•

Using circlip pliers to remove the circlips, disassemble the

transmission shaft.

Special Tool - Out side Circ lip Pliers : 57 0 01 - 144

Transmission Shaft Assembly

•

Apply engine oil liberally to the transmission shaft, gears

and bearings.

•

Replace any circlips that were removed with new ones.

○

Always install circlips [A] so that the opening [B] is aligned

withasplinegroove[C].

Special Tool - Out side Circ lip Pliers : 57 0 01 - 144

•

The drive shaft gears can be identified by size; the

smallest diameter gear is 1st gear, and the largest is 5th

(KX250) or 6th (KX125). Be sure that all parts are put

back in the correct sequence, and facing the proper di-

rection, and that all circlips and the washers are properly

in place.

ENGINE BOTTOM END/TRANSMISSION 8-17

Transmission

KX125:

A. 1st gear (13T; part of drive shaft)

B. 5th gear (24T; plain side faces right)

C. 3rd/4th gear (17T/17T; larger gear faces right)

D. 6th gear (25T; plain side faces left)

E. 2nd gear (14T; stepped side faces left)

F. Circlip

KX250:

A. 1st gear

(15T;partofdriveshaft)

B. 5th gear

(23T; dog recesses face left)

3rd gear

(17T; fork groove goes to the left side of

the gea r teeth)

D. 4th gear

(21T; dog recesses face right)

E. 2nd gear

(16T; chamfered side faces right)

Circlip

•

The output shaft gears can be identified by size; the

largest diameter gear is 1st gear, and the s mallest is

5th (KX250) or 6th (KX125). Be sure that all parts are

put back in the c orrect sequence and facing the proper

direction, and that all circlips are properly in place.

KX125:

A. 2nd gear

(26T; dog recesses face right)

B. 6th gear

(25T; fork groove goes to the right side of

the gea r teeth)

3rd gear

(26T; dog recesses face left)

D. 4th g ear

(22T; dog recesses face right)

E. 5th gear

(27T; fork groove goes to the left side of

the gea r teeth)

F. 1st gear

(31T; plain side faces right)

G. Circlip

KX250:

A. 2nd gear

(23T; dog recesses face right)

B. 4th gear

(21T; fork groove goes to the right side of

the gea r teeth)

3rd gear

(20T; dog recesses face left)

D. 5th gear

(20T; fork groove goes to the left side of

the gea r teeth)

E. 1st gear

(27T; dog recesses face left)

Circlip

G. Collar

•

Check that each gear spins or slides freely on the trans-

mission shaft without binding after assembly.

8-18 ENGINE BOTTOM END/TRANSMISSION

Transmissio n

Shift Drum and Fork Installation

•

Apply a little engine oil to the shift fork [A] ears, and fit the

shift forks into the gear grooves.

Shift Fork Identification

KX125:

Drive shaft 3rd gear and 4th

gear shift fork [A]

ears are shorter than those of

the other two shift forks

Output shaft 5th ge a r shift fork

[B]

guide pin goes to left side of

the ears

Output shaft 6th ge a r shift fork

[C]

guide pin goes to right side of

the ears

KX250:

Drive shaft 3rd gear and 4th

gear shift fork [A]

ears are shorter than those of the

other two shift forks

Output shaft 4th gear shift

fork [B]

guide pin goes to center side of

the ears

Output shaft 5th gear shift

fork [C]

guide pin goes to left side of the

ears

•

Tighten the shift drum bearing retaining screws or bolts.

Torque - Shift Drum Bearing Retaining Screws: 6.4 N·m

(0.65 kgf·m, 56 in·lb) (KX125 ∼ M1)

Shift Drum Bearing Retaining bolts: 8.8 N·m (0.9

kgf·m, 78 in·lb) (KX250), (KX125-M2 ∼)

•

Install the shift dram [A].

•

Fit the shift fork guide pins into the corresponding shift

drum grooves.

•

Apply a little engine oil to the shift rods [A], and slide them

into the shift forks [B].

•

Holding the shift drum with the suitable too and tighten

the shift drum operating plate bolt.

Torque - Shift Drum Operating Cam Bolt: 24 N·m (2.4 kgf·m,

17.0 ft·lb)

ENGINE BOTTOM END/TRANSMISSION 8-19

Transmission

Shift Fork Bending

•

Visually inspect the shift forks, and replace any fork that is

bent. A bent fork could cause difficulty in s hifting, or allow

the transmission to jump out of gear when under power.

A. 90°

Shift Fork/Gear Groove Wear

•

Measure the thickness of the shift fork ears [A], and mea-

sure the width [B] of the shift fork grooves in the transmis-

sion gears.

If the thickness of a shift fork ear is less than the service

limit, the shift fork must be replaced.

Shift Fork Ear Thickness

Standard:

KX125

4.9 ∼ 5.0 mm (0.1768 ∼ 0.1969 in.)

KX250

4.4 ∼ 4.5 mm (0.1732 ∼ 0.1772 in.)

Service Limit:

KX125

4.8 mm (0.189 in.)

KX250

4.3 mm (0.169 in.)

If a gear shift fork groove is worn over the service limit,

the gear must be replaced.

Shift Fork Groove Width

Standard:

KX125 5.05 ∼ 5.15 mm (0.1988 ∼ 0.2028 in.)

KX250 4.55 ∼ 4.65 mm (0.1791 ∼ 0.1830 in.)

Service Limit:

KX125 5.25 mm (0.207 in.)

KX250 4.75 mm (0.187 in.)

Shift Fork Guide Pin/Shift Drum Groove We ar

•

Measure the diameter [A] of each shift fork guide pin, and

measure the width [B] of each shift drum groove.

If the guide pin on any shift fork is less than the service

limit, the fork must be replaced.

Shift Fork Guide Pin Diameter

Standard: 5.90 ∼ 6.00 mm (0.2323 ∼ 0.2362 in.)

Service Limit: 5.80 mm (0.228 in.)

If any shift drum groove is worn over the service limit, the

drum must be replaced.

Shift Drum Groove Width

Standard: 6.05 ∼ 6.20 mm (0.2382 ∼ 0.2440 in.)

Service Limi t: 6 .2 5 mm (0.246 in . )

8-20 ENGINE BOTTOM END/TRANSMISSION

Transmissio n

Gear Damage

•

Visually inspect the gear teeth on the transmission gears.

Repair lightly damaged gear teeth with an oilstone. The

gear must be replaced if the teeth are badly damaged.

When gear is repaired or replaced, the driving gear should

also be inspected and repaired or replaced if necessary.

Gear Dog/Gear Dog Hole Damage

•

Visually inspect the gear dogs [A] and gear dog holes [B].

Replace any damaged gears or gears w ith excessively

worn dogs or dog holes.

Ball Bearing Wear

•

Check the ball bearing on the crankcase.

Since the ball bearings are made to extremely close toler-

ances, the wear must be judged by feel rather than mea-

surement. Clean each bearing in a high-flash point sol-

vent, dry it (do not spin the bearing while it is dry), and oil

it with transmission oil.

○

Spin the bearing by hand to check its condition.

If the bearing is noisy, does not spin smoothly, or has any

rough spots, replace it.

WHEELS/TIRES 9-1

Wheels/Tires

Table of Contents

Exploded View........................................................................................................................ 9-2

Specifications ......................................................................................................................... 9-4

Special Tools .......................................................................................................................... 9-5

Wheels (Rims) ........................................................................................................................ 9-6

Front Wheel Removal ....................................................................................................... 9-6

Front Wheel Installation .................................................................................................... 9-7

Rear Wheel Removal........................................................................................................ 9-8

Rear Wheel Installation..................................................................................................... 9-8

Wheels Inspection............................................................................................................. 9-10

Spoke Tightness Inspection.............................................................................................. 9-10

Rim Runout Inspection ...................................................................................................... 9-10

Axle Inspection..................................................................................................................9-10

Tires........................................................................................................................................ 9-11

Air Pressure Inspection/Adjustment.................................................................................. 9-11

Tires Inspection.................................................................................................................9-11

Tire Removal.....................................................................................................................9-11

Installation......................................................................................................................... 9-12

Hub Bearings.......................................................................................................................... 9-13

Hub Bearing Removal....................................................................................................... 9-13

Hub Bearing Installation.................................................................................................... 9-13

Hub Bearing Inspection..................................................................................................... 9-13

9-2 WHEELS/TIRES

Exploded View

WHEELS/TIRES 9-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Spoke Nipple 2.2 0.22 19 in·lb

2 Front Axle Nut 78 8.0 58

3 Front Axle Clamp Bolts 20 2.0 14.5

4 Rear Axle Nut 108 11.0 80

5. Spoke

6. Front Tire

7. Rim

8. Front Axle

9. Swingarm

10. Rear Tire

11. Rear Axle

A: KX125/250-M1 model

B: KX125/250-M2 model∼

G: Apply grease.

WL: Apply soap and water solution, or rubber lubricant.

9-4 WHEELS/TIRES

Specifications

Item Standard Service Limit

Wheels (Rims)

Rim Runout (with tire installed):

Axial 1.0 mm (0.039 in.) or less 2 mm (0.079 in.)

Radial 1.0 mm (0.039 in.) or less 2 mm (0.079 in.)

Axle Runout/ 100 mm 0.1 mm (0.004 in.) or less 0.2 mm (0.008 in.)

KX125

Rim Size:

Front 21 × 1.60 –––

Rear 19 × 1.85 –––

KX250

Rim Size:

Front 21 × 1.60 –––

Rear 19 × 2.15 –––

Tires Air Pressure

Front and Rear 100 kPa (1.0 kgf/cm², 14 psi) –––

Tires

Standard Tire:

KX125

Front:

Size 80/100-21 51M –––

Make DUNLOP

Type:

(KX125-M1 ∼ M2) D739FA, Tube (EUR) D755FJ, Tube

(KX125-M3 ∼) D742F, Tube (other than EUR)

Rear:

Size 100/90-19 57M –––

Make DUNLOP

Type:

(KX125-M1 ∼ M2) D739, Tube (EUR) D755G, Tube

(KX125-M3 ∼) D756, Tube (other than EUR)

KX250

Front:

Size 80/100-21 51M –––

Make BRIDGESTONE (EUR) DUNLOP

Type M601, Tube (EUR) D755FJ, Tube

Rear:

Size 110/90-19 62M –––

Make BRIDGESTONE (EUR) DUNLOP

Type M602, Tube (EUR) D755J, Tube

(EUR): Europe Model

WHEELS/TIRES 9-5

Special Tools

Inside Circlip Plie r s:

57001-143

Rim Protector:

57001-1063

Bead Breaker Assembly:

57001-1072

Bearing Driver Set:

57001-1129

Jack:

57001-1238

9-6 WHEELS/TIRES

Wheels (Rims)

Front Wheel Removal

•

Using the jack [A] under the frame, and stabilize the mo-

torcycle.

Special Tool - Jack: 57001-1238

•

Place a jack under the engine to raise the front wheel off

the ground.

•

For KX125/250-M1 model, unscrew the guard screw [A]

and remove the guard [B].

•

Unscrew the axle nut [A].

•

Loosen the left axle clamp bolts [B].

•

For KX125/250-M2 model∼; as shown in the figure.

•

Loosen the right axle clamp bolts [A], remove the axle [B],

and pull out the wheel. Take off the collar [C] and cap [D]

from each side of the front hub.

CAUTION

Do not lay the wheel on the ground with the disc

facing down. This can damage or warp the disc.

Place blocks under the wheel so the disc does not

touch the ground.

WHEELS/TIRES 9-7

Wheels (Rims)

•

For KX125/250-M2 model∼; as shown in the figure.

•

Insert a wood wedge between the disc brake pads this

prevents them from being moved out of their proper posi-

tion, s hould the brake lever be squeezed accidentally.

Front Wheel Installation

•

Apply grease to the seals.

•

Fit the projection on the cap to the groove on the collar.

•

Install the caps [B] collars [A] o n the left (longer collar)

and right (shorter collar) side of the hub.

•

Insert the axle [C] from right side.

•

Unbolt the right axle clamp bolts [D] temporally.

•

Tighten the axle nut [E].

Torq ue - Fron t Axle Nut : 78 N·m (8.0 kgf ·m , 58 ft·lb )

•

Remove the jack. Push and release the handlebars five

times or more apply the front brake to move the front forks

so that the axle shaft has a snug fit with the axle holder.

•

Tighten the left axle clamp bolts [F] first, and tighten the

right axle clamp bolts.

Torque - Front Axle Clamp Bolts: 20 N·m (2.0 kgf·m, 14.5

ft·lb)

NOTE

○

Tighten the two clamp bolts alternately two times to en-

sure even tightening torque.

•

For KX125/250-M2 model∼; as shown in the figure.

•

Check the front brake for good braking power and no

brake drag.

WARNING

Do not attempt to drive the motorcycle until a full

brake lever is obtained by pumping the brake lever

until the pads are against the disc. The brake will

not function on the first application of the lever if

this is not done.

9-8 WHEELS/TIRES

Wheels (Rims)

Rear Wheel Removal

•

Using the jack under the frame so that the rear wheel is

raised off the ground.

Special Tool - Jack: 57001-1238

•

Remove the clip [A] from the master link using pliers, and

free the drive chain [B] from the rear sprocket.

•

Remove

Disc Cover [A]

Cotter Pin [B]

Axle Nut [C]

•

Pullouttheaxle[D].

•

Move the rear wheel back w ith the rear caliper installed.

•

Take off the collar and cap from the each side of the rear

hub.

CAUTION

Do not lay the wheel on the ground with the disc

facing down. This can damage or warp the disc.

Place blocks under the wheel so the disc does not

touch the ground.

•

Insert a wood wedge between the brake pads. This pre-

vents them from being moved out of their proper position,

should the brake pedal be squeezed accidentally.

Rear Wheel Installation

•

Fit the brake holder stop [A] with the stop grooves [B]

against the swingarm stop space [C] with the stop pro-

jection [D].

WHEELS/TIRES 9-9

Wheels (Rims)

•

Fit the projection on the cap to the groove on the collar.

•

Install the collars [A] on the left and right side of the hub.

•

Install the drive chain. Install the master link clip [A] so

that the closed end of the “U” [B] points in the direction of

chain rotation [C].

•

Check the drive chain slack (see Final Drive chapter).

•

Tighten the axle nut.

Torque - Rear Axle Nut: 108 N·m (11 kgf·m, 80 ft·lb)

•

Install the new cotter pin [A] and spread its end.

NOTE

○

When inserting the cotter pin, if the slots in the nut do

not align with the cotter pin hole in the axle shaft, tighten

the nut clockwise [A] up to next alignment.

○

It should be within 30 degree.

○

Loosen once tighten again when the s lot goes past the

nearest hole.

•

Install disc cover.

•

Check the rear brake for good braking power and no

brake drag.

WARNING

Do not attempt to drive the motorcycle until a full

brake pedal is obtained by pumping the brake pedal

until the pads are against the disc. The brake will

not function on the first application of the pedal if

this is not done.

9-10 WHEELS/TIRES

Wheels (Rims)

Wheels Inspection

•

Place the jack under the frame so that the front/rear wheel

is raised off the ground.

Special Tool - Jack: 57001-1238

•

Spin the wheel lightly, and check for roughness or binding.

If roughness or binding is found, replace the hub bearings.

•

Visually inspect the front and rear axles for damage.

If axle is damaged or bent, replace it.

Spoke Tightness Inspection

•

Refer to the Spoke Tightness Inspection in the Periodic

Maintenance chapter.

Rim Runout Inspection

•

Refer to the Rim Runout Inspection in the Periodic Main-

tenance chapter.

Axle Inspection

•

Visually inspect the front and rear axle for damages.

If the axle is damaged or bent, replace it.

•

Place the axle in V blocks that are 100 mm (3.937 in.) [A]

apart, and set a dial gauge on the axle at a point halfway

between the blocks. Turn the axle to measure the runout.

The difference between the highest and lowest dial read-

ings is the amount of runout.

Axle Runout/100 mm (3.937 in.)

Standard: 0.1 mm (0.004 in.) or less

Service Limit: 0.2 mm (0.008 in.)

If runout exceeds the service limit, replace the axle.

WHEELS/TIRES 9-11

Tires

Air Pressure Inspection/Adjustment

•

Refer to the Air Pressure Inspection/Adjustment in the Pe-

riodic Maintenance c hapter.

Tires Inspection

•

Refer to the Tires Inspection in the Periodic Maintenance

chapter.

Tire Removal

CAUTION

Do not lay the wheel on the ground with the disc

facing down. This can damage or warp the disc.

Place blocks under the wheel so the disc does not

touch the ground.

•

Remove the wheel from the motorcycle (see Wheels Re-

moval).

•

To maintain wheel balance, mark [A] the valve stem posi-

tion on the tire with chalk so that the tire can be reinstalled

in the same position.

•

Take out the valve core [B] to let out the air.

•

Remove the valve stem nut [C].

○

When handling the rim, be careful not to damage the rim

flanges.

•

Loosen the bead protector nut.

•

Lubricate the tire beads and rim flanges on both sides with

a s oap and water solution or rubber lubricant. This helps

the tire beads slip off the rim flanges.

CAUTION

Never lubricate with mineral oil (engine oil) or gaso-

line because they will cause deterioration of the tire.

•

Break the beads away from both sides of the rim with the

bead breaker [A].

Special Tool - Bead Breaker Assembly: 57001-1072

•

Step on the side of the tire opposite valve stem, pry the

tire off the rim with the tire iron [A] of the bead breaker

protecting the rim with rim protectors [B].

Special Tools - Rim Protector: 57001-1063

Bead Breaker Assembly: 57001-1072

CAUTION

Take care not to inset the tire irons so deeply that

the tube gets damaged.

•

Remove the tube when one side of the tire is pried off.

•

Pry the tire off the rim.

9-12 WHEELS/TIRES

Tires

Installation

NOTE

○

The tires should be installed so that the year and week

of manufacture [A] or the ID serial faces to left side.

•

Inspect the rim and tire, and replace them if necessary.

•

Install the tube.

•

Apply a soap and water solution, or rubber lubricant to the

rim flange and tire beads.

•

Position the tire on the rim so that the valve [A] is at the tire

balance mark [B] (the chalk mark made during r emoval,

or the yellow paint mark on a new tire. see Removal).

•

Insert the valve stem into the rim, and screw the nut on

loosely.

•

Fit the rim protectors and use tire irons to install the tire

bead.

NOTE

○

To prevent rim damage, be sure to place the rim protec-

tors at any place the tire irons are applied.

•

Pry one side of the tire back onto the rim. Fit the bead

protector into the tire.

•

Pry the other side of the tire onto the rim, starting at the

side opposite the valve.

○

Take care not to insert the tire irons so deeply that the

tube is damaged.

•

Install the other side of the tire bead onto the rim in the

same manner.

•

Check that the tube is not pinched between the tire and

rim.

•

Tighten the bead protector nut and valve stem nut, and

put on the valve cap.

•

Check and adjust the air pressure after installing.

WHEELS/TIRES 9-13

Hub Bearings

Hub Bearing Removal

•

Remove the wheel (see Wheel Removal).

CAUTION

Do not lay the wheel on the ground with the disc

facing down. This can damage or warp the disc.

Place blocks under the wheel so that the disc does

not touch the ground.

•

Remove the o il seals and circlips.

•

Remove the hub bearing by tapping evenly around the

bearing inner race as shown.

[A] Bar

[B] Distance Collar

[C] Hub Bearing

Hub Bearing Installation

•

Before installing the wheel bearings, blow any dirt or for-

eign particles out of the hub [B] with compressed air to

prevent contamination of the bearings.

•

Replace the bearings with new ones.

•

Lubricate them and install them using the bearing driver

set [A] so that the marked or shielded sides face out.

○

Press in the bearings until they are bottomed.

Special Tool - Bearing Driver Set: 57001-1129

•

Replace the circlips and oil seals with new ones.

•

Press in the oil seals [A] so that the seal surface is flush

[B] with the end of the hole.

•

Apply high temperature grease to the oil seal lips.

Special Tool - Bearing Driver set: 57001-1129

Hub Bearing Inspection

NOTE

○

It is not necessary to remove any bearings for inspec-

tion. If any bearings are removed, they will need to be

replaced with new ones.

•

Spin [A] it by hand to check its condition.

If it is noisy, does not spin smoothly, or has any rough

spots, it must be replaced.

•

Examine the bearing seal [B] for tears or leakage.

If the seal is torn or is leaking, replace the bearing.

FINAL DRIVE 10-1

Final Drive

Table of Contents

Exploded View........................................................................................................................ 10-2

Specifications ......................................................................................................................... 10-4

Special Tools .......................................................................................................................... 10-5

Drive Chain............................................................................................................................. 10-6

Drive Chain Slack Inspection ............................................................................................ 10-6

Drive Chain Slack Adjustment .......................................................................................... 10-6

Wheel Alignment Inspection ............................................................................................. 10-6

Wheel Alignment Adjustment............................................................................................ 10-6

Drive Chain Wear Inspection ............................................................................................ 10-6

Drive Chain Lubrication..................................................................................................... 10-6

Drive Chain Removal ........................................................................................................ 10-6

Drive Chain Installation ..................................................................................................... 10-6

Sprockets................................................................................................................................ 10-7

Engine Sprocket Removal ................................................................................................ 10-7

Engine Sprocket Installation ............................................................................................ 10-7

Rear Sprocket Removal.................................................................................................... 10-7

Rear Sprocket Installation................................................................................................. 10-7

Sprocket Wear Inspection................................................................................................. 10-7

Rear Sprocket Warp Inspection ........................................................................................ 10-7

10-2 FINAL DRIVE

Exploded View

FINAL DRIVE 10-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Rear Sprocket Nuts 34 3.5 25

2 Rear Axle Nut 108 11.0 80

3 Engine Sprocket Cover Bolts 4.9 0.5 43 in·lb

4. Engine Sprocket

5. Output Shaft

6. Chain Slipper

7. Swingarm

8. Chain Guide

9. Locknut

10. Adjusting Bolt

11. Chain Adjuster

12. Drive Chain

13. Rear Sprocket

14. Rear Axle

A: KX125-M1 ∼ M2 Model

G: Apply grease.

O: Apply oil.

10-4 FINAL DRIVE

Specifications

Item Standard Service Limit

Drive Chain

Chain Slack 52 ∼ 62 mm (2.05 ∼ 2.44 in.) –––

Chain 20-link Length 317.5 ∼ 318.2 mm (12.50 ∼ 12.53 in.) 323 mm (12.72 in.)

Standard Chain:

Make:

DAIDO

–––

Type: D.I.D 520DMA2 –––

Length:

KX125-M1 112 Links –––

KX125-M2 ∼ 114 Links –––

KX250 114 Links –––

Sprocket

Rear Sprocket Warp 0.4 mm (0.016 in.) or less 0.5 mm (0.020 in.)

FINAL DRIVE 10-5

Special Tools

Outside Circlip Pliers:

57001-144

Jack:

57001-1238

10-6 FINAL DRIVE

Drive Chain

Drive Chain Slack Inspection

•

Refer to the Drive Chain Slack Inspection in the Periodic

Maintenance chapter.

Drive Chain Slack Adjustment

•

Refer to the Drive Chain Slack Adjustment in the Periodic

maintenance chapter.

Wheel Alignment Inspection

•

Check that the rear end [A] of the left chain adjuster aligns

with the same swing arm mark [B] as the right chain ad-

juster.

WARNING

Misalignment of the wheel will result in abnormal

wear, and may result in an unsafe riding condition.

Wheel Alignment Adjustment

This p rocedure is the same as Drive Chain Slack Adjust-

ment.

Drive Chain Wear Inspection

•

Refer to the Drive Chain Wear Inspection in the Periodic

Maintenance chapter.

Drive Chain Lubrication

•

Refer to the Drive Chain Lubrication in the Periodic Main-

tenance chapter.

Drive Chain Removal

•

Remove the engine sprocket cover.

•

Remove the clip [A] from the master link using pliers, and

free the drive chain from the rear sprocket.

•

Remove the drive chain from the chassis.

Drive Chain Installation

•

Fit the drive chain back onto the sprockets with the ends

at the rear sprocket.

•

Install the master link from the frame side.

•

Install the clip [A] so that the closed end of the "U" [B]

pointed in the direction of chain rotation [C].

•

Adjust the drive chain slack (see Drive Chain Slack Ad-

justment).

•

Check the rear brake (see the Brakes chapter).

FINAL DRIVE 10-7

Sprockets

Engine Sprocket Re mova l

•

Remove:

Engine Sprocket Cover [A]

Drive Chain [B] (free of engine sprocket)

•

Remove the circlip [C], and pull off the engine sprocket

[D].

Special Tool - Outside Circlip Pliers: 57001-144

Engine Sprocket Installa tion

•

Replace the circlip with a new one.

•

Install the circlip so that the tooth is aligned with a spline

groove.

Special Tool - Outside Circlip Pliers: 57001-144

•

For KX250, clamp the air vent hoses with clamps which

are installed together with engine sprocket cover.

•

Tighten:

Torque - Engine Sprocket Cover Bolts: 4.9 N·m (0.5 kgf·m,

43 in·lb)

Rear Sprocket Removal

•

Remove the rear wheel (see Wheels/Tires chapter).

CAUTION

Do not lay the wheel on the ground with the disc

facing down. This can damage or warp the disc.

Place blocks under the wheel so that the disc does

not touch the ground.

•

Unscrew the rear sprocket bolts [A], and remove the rear

sprocket [B].

Rear Sprocket Installation

•

Install the rear sprocket [A] so that the marked side [B]

faces out.

•

Install the rear sprocket bolts and tighten the nuts.

Torque - Rear Sprocket Nuts: 34 N·m (3.5 kgf·m, 25 ft·lb)

Sprocket Wear Inspection

•

Refer to the Sprocket Wear Inspection in the Periodic

Maintenance chapter.

Rear Sprocket Warp Inspection

•

Refer to the Rear Sprocket Warp Inspection in the Peri-

odic Maintenance c hapter.

BRAKES 11-1

Brakes

Table of Contents

Exploded View........................................................................................................................ 11-2

Specifications ......................................................................................................................... 11-6

Special Tools .......................................................................................................................... 11-7

Brake Lever, Brake Pedal....................................................................................................... 11-8

Brake Lever Play Adjustment............................................................................................ 11-8

Brake Pedal Position/Pedal Play Adjustment ................................................................... 11-8

Brake Pedal Removal ....................................................................................................... 11-8

Brake Pedal Installation .................................................................................................... 11-9

Brake Fluid ............................................................................................................................. 11-10

Fluid Level Inspection ....................................................................................................... 11-10

Fluid Change..................................................................................................................... 11-10

Bleeding the Brake Line.................................................................................................... 11-11

Caliper .................................................................................................................................... 11-13

Caliper Removal ............................................................................................................... 11-13

Caliper Installation ............................................................................................................ 11-14

Caliper Disassembly ......................................................................................................... 11-14

Caliper Assembly .............................................................................................................. 11-15

Fluid Seal Damage ........................................................................................................... 11-15

Dust Seal and Cover Damage .......................................................................................... 11-15

Piston Cylinder Damage ................................................................................................... 11-16

Caliper Holder Shaft Wear ................................................................................................ 11-16

Brake Pad Removal .......................................................................................................... 11-16

Brake Pad Installation ....................................................................................................... 11-17

Brake Pad Inspection........................................................................................................ 11-17

Master Cylinder ...................................................................................................................... 11-18

Front Master Cylinder Removal ........................................................................................ 11-18

Front Master Cylinder Installation ..................................................................................... 11-18

Rear Master Cylinder Removal......................................................................................... 11-18

Rear Master Cylinder Installation...................................................................................... 11-19

Front Master Cylinder Disassembly .................................................................................. 11-19

Rear Master Cylinder Disassembly ................................................................................... 11-19

Master Cylinder Assembly ................................................................................................ 11-20

Master Cylinder Inspection (Visual Inspection)................................................................. 11-20

Brake Disk .............................................................................................................................. 11-21

Brake Disc Inspection ....................................................................................................... 11-21

Brake Hose............................................................................................................................. 11-22

Brake Hose Removal/Installation...................................................................................... 11-22

Brake Hose Inspection...................................................................................................... 11-22

11-2 BRAKES

Exploded View

BRAKES 11-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Front Master Cylinder Clamp Bolts 8.8 0.9 78 in·lb

2 Brake Lever Pivot Bolt 5.9 0.60 52 in·lb

3 Brake Lever Pivot Bolt Locknut 5.9 0.60 52 in·lb

4 Brake Hose Banjo Bolts 25 2.5 18

5 Brake Pad Bolt 18 1.8 13

6 Caliper Bleed Valve 7.8 0.8 69 in·lb

7 Caliper Mounting Bolts 25 2.5 18

8 Brake Disc Mounting Bolts 9.8 1.0 87 in·lb L

9. Front Brake Reservoir

10. Brake Lever

11. Brake Lever Adjuster

12. Locknut

13. Brake Hose

14. Clamps

15. Front Caliper

16. Brake Pad

17. Piston

18. Front Disc

A: KX125/250-M1 model

B: KX125/250-M2 model ∼

L: Apply a non-permanent locking agent.

R: Replacement Parts

Si: Apply Silicone grease.

11-4 BRAKES

Exploded View

BRAKES 11-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Brake H ose Banjo Bolts 25 2.5 18

2 Rear Master Cylinder Mounting Bolts 9.8 1.0 87 in·lb

3 Rear Master Cylinder Push Rod Locknut 18 1.8 13

4 Caliper Bleed Valve 7.8 0.8 69 in·lb

5 Brake Pad Bolt 18 1.8 13

6 Rear Brake Pad Bolt Plug 2.5 0.25 22 in·lb

Caliper Holder Shaft

27 2.8 20

8 Brake Pedal Mounting Bolt 25 2.5 18 L

9 Brake Disc Mounting Bolts 23 2.3 16.6 L

10. Brake Hose

11. Rear Master Cylinder

12. Brake Pedal

13. Rear Caliper Cover

14. Rear Caliper

15. Piston

16. Brake Pad

17. Rear Disc

G: Apply high temperature grease.

L: Apply a non-permanent locking agent.

R: Replacement Parts

Si: Apply Silicone grease.

11-6 BRAKES

Specifications

Item Standard Service Limit

Brake Adjustment

Brake Lever Play

Adjustable (to suit rider)

–––

Brake Fluid

Recommended Disc Brake Fluid: –––

Type:

Front DOT3 or DOT4 –––

Rear DOT4

Brake Pads

Lining Thickness:

Front 3.8 mm (0.150 in.) 1mm(0.04in.)

Rear

6.4 mm (0.252 in.) 1mm(0.04in.)

Brake Disc

Thickness:

Front 2.85 ∼ 3.15 mm (0.112 ∼ 0.124 in.) 2.5 mm (0.10 in.)

Rear 3.85 ∼ 4.15 mm (0.152 ∼ 0.163 in.) 3.5 mm (0.14 in.)

Runout 0.25 mm (0.098 in.) or less 0.3 mm (0.01 in.)

BRAKES 11-7

Special Tools

Inside Circlip Plie r s:

57001-143

Jack:

57001-1238

11-8 BRAKES

Brake Lever, B rake Pedal

Brake Lever Play Adjustment

•

Refer to the Brake Lever Play Adjustment in the Periodic

Maintenance chapter.

Brake Pedal Positio n/Pedal Play Adjustment

The brake pedal position and pedal play should not be

adjusted. There is no pedal position adjustment device

as such. The only adjustment is master cylinder push rod

length.

NOTE

○

Usually it is not necessary to adjust the push rod length,

but always adjust it when the rear master cylinder [A] is

disassembled.

○

When the brake pedal is in its rest position, measure

the length [B] indicated in the figure.

Push Rod Locknut [C]

Standard Length [B]:

79.3 mm (3.12 in.) (KX125/250-M1)

67.3 mm (2.65 in.) (KX125/250-M2 ∼)

If the length is not within the specified length, adjust the

clevis [A] as follows.

○

Loosen the push rod locknut [B].

○

Pull out the c otter pin [C] and the joint pin [D].

○

Turn the clevis to obtain the specified length.

○

Tighten the locknut.

Torque - Push Rod Locknut: 18 N·m (1.8 kgf·m, 13.0 ft·lb)

○

Install the joint pin and new cotter pin.

NOTE

○

If the pedal position is incorrect after adjusting the mas-

ter cylinder push rod, the brake pedal may be deformed

or incorrectly installed.

Brake Pedal Removal

•

Remove:

Cotter Pin [A]

Joint Pin [B]

Washer

BRAKES 11-9

Brake Lever, Brake Pedal

•

Remove the mounting bolt [A] and take off the brake pedal

and return spring [B].

Brake Pedal Installation

•

Check the pedal O-ring for signs of damage. If necessary,

replace them with new one.

•

Apply high temperature grease to the shaft portion of the

brake pedal, and install the pedal with return spring onto

the frame.

•

Tighten:

Torque - Brake Pedal Mounting Bolt: 25 N·m (2.5 kgf·m, 18

ft·lb)

•

Check the brake pedal position.

•

Install the joint pin, washer and a new cotter pin.

11-10 BRAKES

Brake F luid

WARNING

When working with the disc brake, observe the pre-

cautions listed below.

1. Never reuse old brake fluid.

2. Do not use fluid from a container that has been left

unsealed or that has been open for a long time.

3. Do not mix two types and brands of fluid for use in

the brake. This lowers the brake fluid boiling point

and could cause the brake to be ineffective. It may

also cause the rubber brake parts to deteriorate.

4. Don’t leave the reservoir cap off for any length of

time to avoid moisture contamination of the fluid.

5. Don’t change the fluid in the rain or when a strong

wind is blowing.

6. Except for the disc pads and disc, use only disc

brake fluid, isopropyl alcohol, or ethyl alcohol for

cleaning of the brake parts. Do not use any other

fluid for cleaning these parts. Gasoline, engine oil,

or any other petroleum distillate will cause deterio-

ration of the rubber parts. Oil spilled on any part will

be difficult to wash off completely and will eventually

deteriorate the rubber used in the disc brake.

7. When handling the disc pads or disc, be careful that

no disc brake fluid or any oil gets on them. Clean off

any fluid or oil that inadvertently gets o n the pads or

disc with a high-flash point solvent. Do not use one

which will leave an oily residue. Replace the pads

with new ones if they cannot be cleaned satisfacto-

rily.

8. Brake fluid quickly ruins painted surfaces; any

spilled fluid should be completely wiped up imme-

diately.

9. If any of the brake line fittings or the bleed valve is

opened at any time, the AIR MUST BE BLED FROM

THE BRAKE LINE.

Fluid Level Inspection

•

Refer to the Brake Fluid Level Inspection in the Periodic

Maintenance chapter.

Fluid Change

•

Refer to the Brake Fluid Change in the Periodic Mainte-

nance chapter.

BRAKES 11-11

Brake Fluid

Bleeding the Brake Line

The brake fluid has a very low compression coefficient so

that almost all the movement of the brake lever or pedal

is transmitted directly to the caliper for braking action. Air,

however, is easily compressed. When air enters the brake

lines, brake lever or pedal movement will be partially used

in compressing the air. This will make the lever or pedal feel

spongy, and there will be a loss in braking power.

WARNING

Be sure to bleed the air from the brake whenever

brake lever or pedal action feels soft or spongy, af-

ter the brake fluid is changed, or whenever a brake

line fitting has been loosened for any reason.

NOTE

○

The procedure to bleed the front brake line is as follows.

Bleeding the rear brake line is the same as for the front

brake.

•

Remove the reservoir cap, and check that there is plenty

of fluid in the reservoir.

•

With the reservoir cap off, slowly pump the brake lever

several times until no air bubbles can be seen rising up

through the fluid from the holes at the bottom of the reser-

voir.

○

Bleed the air completely from the master cylinder by this

operation.

•

Install the reservoir cap.

•

Attach a clear plastic hose to the bleed valve on the

caliper, and run the other end of the hose into a con-

tainer.

•

Bleed the brake line and the caliper as follows:

○

Repeat this operation until no more air can be seen com-

ing out into the plastic hose.

1. Pump the brake lever until it becomes hard, and apply

the brake and hold it [A].

2. Quickly open and close the bleed valve while holding the

brake applied [B].

3. Release the brake [C].

NOTE

○

The fluid level must be checked often during the bleed-

ing operation and replenished with fresh brake fluid as

necessary. If the fluid in the reservoir runs almost out

any time during bleeding operation, the bleeding opera-

tion must be done over again from the beginning since

air will have entered the line.

○

Tap the brake hose lightly from the caliper to the reser-

voir for easier bleeding.

11-12 BRAKES

Brake F luid

•

Remove the clear plastic hose.

•

Tighten the bleed valves, and install the rubber caps.

Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)

•

Check the fluid level.

•

After bleeding is done, check the brake for good braking

power, no brake drag, and no fluid leakage.

WARNING

Do not attempt to drive the motorcycle until a full

brake lever or pedal is obtained by pumping the

brake lever or pedal until the pads are against the

disc. The brake will not function on the first appli-

cation of the lever or pedal if this in not done.

BRAKES 11-13

Caliper

Caliper Removal

Front Brake

•

Loosen the banjo bolt [A] so as not to spill brake fluid.

•

Remove the caliper mounting bolts [B].

•

Remove the banjo bolt and take off the brake hose from

the caliper [C].

•

If the caliper is to be disassembled after removal and if

compressed air is not available, remove the piston using

the following steps before disconnecting the brake hose

from the caliper.

○

Remove the pads.

○

Pump the brake lever to remove the piston.

•

For KX125/250-M2 model ∼; as shown in the figure.

Rear Brake

•

Unbolt the guard bolts [A] and remove the rear caliper

guard [B].

•

Loosen the banjo bolt [C] so as not to spill brake fluid.

•

Loosen the brake pad bolt [A] and caliper holder shaft [B]

before the caliper removal if the caliper is to be disassem-

bled.

NOTE

○

If the caliper is to be disassembled after removal and

compressed air is not available, disassemble the caliper

before brake hose removal (see Caliper Disassembly).

•

Remove the rear wheel. (see Wheels/Tires chapter)

•

Unscrew the banjo bolt and remove the brake hose [C]

from the caliper (see Brake Hose Removal/Installation).

CAUTION

Immediately wipe up any brake fluid that is spilled.

11-14 BRAKES

Caliper

Caliper Installation

•

Tighten the brake pad bolts if it was removed.

Torque - Brake Pad Bolts: 18 N·m (1.8 kgf·m, 13 ft·lb)

Front Brake:

•

Install the caliper and tighten the bolts.

Torque - Caliper Mounting Bolts: 25 N·m (2.5 kgf·m, 18.0

ft·lb)

Rear Brake:

•

Before install the caliper, install the rear wheel (see

Wheels/Tires chapter).

•

Install the brake hose lower end.

○

Replace the washers that are o n each side of hose fitting

with new ones.

•

Tighten:

Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)

•

Bleed the brake line (see Bleeding the Brake Line).

•

Check the brake for good braking power, no brake drag,

and no fluid leakage.

WARNING

Do not attempt to drive the motorcycle until a full

brake lever or pedal is obtained by pumping the

brake lever or pedal until the pads are against the

disc. The brakes will not function on the first appli-

cation of the lever or pedal if this is not done.

Caliper Disassembly

•

Remove the front/rear caliper (see Caliper removal).

•

Remove the pads and spring (see Pad Removal).

•

Remove the caliper holder, shaft rubber friction boot and

cover.

•

Using compressed air, remove the piston(s).

○

Cover the caliper opening with a clean, heavy cloth [A].

○

Remove the piston(s) by lightly applying compressed air

[B] to the hose joint opening.

WARNING

To avoid serious injury, never place your fingers or

palm inside the caliper opening. If you apply com-

pressed air into the caliper, the piston(s) may crush

your hand or fingers.

NOTE

○

If the caliper is to be disassembled after removal and

compressed air is not available, remove the piston(s)

using the following three steps before disconnecting the

brake hose from the caliper.

○

Prepare a container for brake fluid, and perform the

work above it.

○

Remove the pads and spring (see Pad Removal).

○

Pump the brake lever or pedal to remove the caliper

piston(s).

•

Remove the dust s eal(s) and fluid seal(s).

•

Remove the bleed valve and rubber cap.

BRAKES 11-15

Caliper

Caliper Assembly

•

Clean the caliper parts except for the pads.

CAUTION

For cleaning the parts, use only disc brake fluid,

isopropyl alcohol, or ethyl alcohol.

•

Tighten the bleed valve with rubber cap.

Torque - Caliper Bleed Valve: 7.8 N·m (0.8 kgf·m, 69 in·lb)

•

Replace the fluid seals which are removed with new ones.

○

Apply brake fluid t o the fluid seals [A], and install them

into the cylinders by hand.

•

Replace the dust seals with new ones if they are dam-

aged.

○

Apply brake fluid to the dust seals [B], and install them

into the cylinders by hand.

•

Apply brake fluid to the outside of the pistons [C], and

push them into each cylinder by hand.

•

Install t he anti-rattle spring [A] in the caliper as shown.

•

Replace the shaft rubber friction boot [A] and dust cover

[B] if they are damaged.

•

Apply a thin coat of silicone grease to the caliper holder

shafts [C] and holder holes (PBC is a s pecial high tem-

perature, water-resistant grease).

○

For rear caliper, tighten the caliper holder shaft.

Torque - Caliper Holder Shaft: 27 N·m (2.8 kgf·m, 20 ft·lb)

•

Install the pads (see Pads Installation).

•

Wipe up any spilled brake fluid on the caliper.

Fluid Seal Damage

The fluid seal around the piston maintains the proper

pad/disc clearance. If this seal is not in good condition,

pad wear will increase, and constant pad drag on the disc

will raise brake and brake fluid temperature.

•

Replace the fluid seals under any of the following condi-

tions: (a) fluid leakage around the pad; (b) brakes over-

heat; (c) there is a large difference in left and right pad

wear; (d) the seal is stuck to the piston. If the fluid seal is

replaced, replace the dust seal as well. Also, replace all

seals every other time the pads are changed.

Dust Seal and Cover Damage

•

Check that the dust seals and covers are not cracked,

worn, swollen, or otherwise damaged.

If they show any damage, replace them.

11-16 BRAKES

Caliper

Piston Cylinder Damage

•

Visually inspect the piston and cylinder surfaces.

Replace the cylinder and piston if they are badly scored

or rusty.

Caliper Holder Shaft Wear

The caliper body must slide smoothly on the caliper holder

shafts. If the body does not slide smoothly, one pad will

wear more than the other, pad wear will increase, and con-

stant drag on the disc will raise brake and brake fluid tem-

perature.

•

Check too see if the caliper holder shafts are not badly

worn or stepped, or the rubber friction boot is not dam-

aged.

If the shafts or rubber friction boot are damaged, replace

the s hafts, rubber friction boot, and the caliper holder.

Brake Pad Removal

•

Remove the plug and the pad bolt [A].

•

Take the piston side pad [B].

•

Push the caliper holder toward the piston, and then re-

move another pad [C] from the caliper holder.

•

For KX125/250-M2 model∼; as shown in the figure.

BRAKES 11-17

Caliper

Brake Pad Installation

•

Push the caliper pistons in by hand as far as they will go.

•

Install the piston side pad first, and then another pad.

•

Tighten the brake pad bolt and plug.

Torque - Brake Pad Bolt: 18 N·m (1.8 kgf·m, 13 ft·lb)

Rear Brake Pa d Bolt Plug: 2.5 N·m (0.2 5 kgf·m, 22

in·lb)

•

Check the brake for good braking power, no brake drag,

and no fluid leakage.

WARNING

Do not attempt to drive the motorcycle until a full

brake lever or pedal is obtained by pumping the

brake lever or pedal until the pads are against the

disc. The brake will not function on the first appli-

cation of the lever or pedal if this is not done.

Brake Pad Inspection

•

Refer to the Brake Pad Wear Inspection in the Periodic

Maintenance chapter.

11-18 BRAKES

Master Cylinder

CAUTION

Brake fluid quickly ruins painted or plastic sur-

faces; any spilled fluid should be completely

wished up immediately.

Front Master Cylinder Removal

•

Remove the banjo bolt [A] to disconnect the upper brake

hose from the master cylinder (see Brake Hose Re-

moval/Installation).

•

When removing the brake hose, temporarily secure the

end of the brake hose to some high place to keep fluid

loss to a minimum.

•

Unscrew the clamp bolts [B], and take off the master cylin-

der [C] as an assembly with the reservoir and brake lever.

Front Master Cylinder Installation

•

Position the master cylinder so that the vertical parting

line [A] of the front master cylinder clamps align with the

punch mark [B] on the handlebar.

•

The master cylinder clamp must be installed with the ar-

row mark [A] upward.

○

Tighten the upper clamp bolt [B] first, and then the lower

clamp bolt [C] There w ill be a gap at the lower part of the

clamp after tightening.

Torque - Master Cylinder Clamp Bolts: 8.8 N·m (0.9 kgf·m,

78 in·lb)

•

Replace the washers that are o n each side of hose fitting

with new ones.

•

Tighten the brake hose banjo bolt.

Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)

•

Bleed the brake line (see Bleeding the Brake Line).

•

Check the brake for good braking power, no brake drag,

and no fluid leakage.

Rear Master Cylinder Removal

•

Remove the cotter pin [A].

•

Pull off the joint pin [B] with washer.

NOTE

○

Pull off the joint pin while pressing down the brake

pedal.

•

Unscrew the master cylinder mounting bolts [C], and re-

move the master cylinder.

•

Unscrew the brake hose banjo bolt [D] (see Brake Hose

Removal/Installation).

•

When removing the brake hose, temporarily secure the

end of the brake hose to some high place to keep fluid

loss to a minimum.

BRAKES 11-19

Master Cylinder

Rear Master Cylinder Installation

•

Replace the cotter pin with a new one.

•

Replace the washers are on each side of hose fitting with

new ones.

•

Tighten the following:

Torque - Brake Hose Banjo Bolt: 25 N·m (2.5 kgf·m, 18 ft·lb)

Rear Master Cylinder Mounting Bolts: 9.8 N·m (1.0

kgf·m, 87 in·lb)

•

Bleed the brake line (see Bleeding the Brake Line).

•

Check the brake for good braking power, no brake drag,

and no fluid leakage.

•

Check the brake pedal position (master cylinder push rod

length).

Front Master Cylinder Disassembly

•

Remove the front master cylinder.

•

Remove the reservoir cap and diaphragm, and pour the

brake fluid into a container.

•

Unscrew the locknut and pivot bolt, and remove the brake

lever.

•

Push the dust cover [A] out of place, and remove the cir-

clip [B].

Special Tool - Inside Circ lip Pliers: 57001-143

•

Remove the washer [C], pull out the piston [D], secondary

cup [E], primary cup [F], and return spring [G].

CAUTION

Do not remove the secondary cup from the piston

since removal will damage it.

Rear Master Cylinder Disassembly

•

Remove the rear master c ylinder.

•

Remove the reservoir cap and diaphragm, and pour the

brake fluid into a container.

•

Slide the dust cover [A] on the push rod [B] out of place,

and remove the retainer [C].

Special Tool - Inside Circ lip Pliers: 57001-143

•

Pull out the push rod with the piston stop [D].

•

Take off the piston [E], secondary cup [F], primary cup [G],

and return spring [H].

CAUTION

Do not remove the secondary cup from the piston

since removal will damage it.

11-20 BRAKES

Master Cylinder

Master Cylinder Assembly

•

Before assembly, clean all parts including the master

cylinder with brake fluid or alcohol.

•

Apply brake fluid to the removed parts and to the inner

wall of the cylinder.

CAUTION

Except for the disc pads and disc, use only disc

brake fluid, isopropyl alcohol, or ethyl alcohol for

cleaning brake parts. Do not use any other fluid for

cleaning these parts. Gasoline, engine oil, or any

other petroleum distillate will cause deterioration of

the rubber parts. Oil spilled on any part will be diffi-

cult to the wash off completely, and will eventually

deteriorate the rubber used in the disc brake.

•

Take care not to scratch the piston or the inner wall of the

cylinder.

•

Tighten the brake lever pivot bolt and the locknut securely.

Master Cylinder Inspection ( Visual Inspection)

•

Disassemble the front and rear master cylinders.

•

Check that there are no scratches, rust or pitting on the

inner wall of each master cylinder [A] and on the outside

of each piston [B].

If a master cylinder or piston shows any damage, replace

them.

•

Inspect the primary [C] and secondary [D] cups.

If a cup is worn, damaged, softened (rotted), or swollen,

the piston assembly should be replace to renew the cups.

If fluid leakage is noted at the brake lever, the piston as-

sembly should be replaced to renew the cup.

•

Check the dust covers [E] for damage.

If they are damaged, replace them.

•

Check that the relief [F] and supply [G] ports are not

plugged.

If the small relief port becomes plugged, the brake pads

will drag on the disc. Blow the ports clean with com-

pressed air.

•

Check the piston return springs [H] for any damage.

If a spring is damaged, replace it.

[K] Rear Master Cylinder.

BRAKES 11-21

Brake Disk

Brake Disc Inspection

•

Visually inspect the disc [A].

If it is scratched or damaged, replace the disc.

•

Measure the thickness of each disc at the point [B] where

it has worn the most.

Replace the disc if it has worn past the service limit.

Thickness

Standard:

Front 2.85 ∼ 3.15 mm 2.85 ∼ 3.15 m m

Rear

3.85 ∼ 4.15 mm (0.152 ∼ 0.163 in.)

Service Limit:

Front

2.5 m m (0.10 i n.)

Rear

3.5 m m (0.14 i n.)

•

Place a jack under the m otorcycle so that the front/rear

wheel is raised off the ground.

Special Tool - Jack: 57001-1238

•

Set up a dial gauge against the disc [A] as illustrated.

○

For the front disc, turn the handlebar fully to one side.

•

Measure the disc runout while rotating the wheel slowly

[B].

If the runout exceeds the service limit, replace the disc.

Runout

Standard: 0.2 5 mm (0.098 in.) or less

Service Limit: 0.3 mm (0.01 in .)

11-22 BRAKES

Brake H ose

Brake Hose Remo v al/Installation

CAUTION

fluid quickly ruins painted or plastic surfaces; any

spilled fluid should be completely wiped up imme-

diately with watered cloth.

•

When removing the brake hose, take care not to spill the

brake fluid on the painted or plastic parts.

•

When removing the brake hose, temporarily secure the

end of the brake hose to some high place to keep fluid

loss to a minimum.

•

There are washers on each side of the brake hose fitting.

Replace them with new ones when installing.

•

When installing the hoses, avoid sharp bending, kinking,

flattening or twisting, and route the hoses according to

the Cable, Harness, Hose Routing section in the General

Information chapter.

•

Tighten the banjo bolts at the hose fittings.

Torque - Brake Hose Banjo Bolts: 25 N·m (2.5 kgf·m, 18

ft·lb)

•

Bleed the brake line after installing the brake hose (see

Bleeding the Brake Line).

Brake Hose Inspection

•

Refer to the Brake Hose and Connection Check in the

Periodic Maintenance chapter.

SUSPENSION 12-1

Suspension

Table of Contents

Exploded View................................... 12-2

Specifications .................................... 12-10

Special Tools ..................................... 12-14

Front Fork .......................................... 12-16

Air Pressure ................................. 12-16

Rebound Damping Adjustment .... 12-16

Compression Damping

Adjustment ................................ 12-17

Fork Oil Level Adjustment

(Simplify) ................................... 12-17

Oil Change/Oil Level Adjustment

(each fork leg) ........................... 12-21

Front Fork Removal ..................... 12-21

Front Fork Installation .................. 12-21

Front Fork Disassembly (each

fork leg) ..................................... 12-22

Front Fork Assembly.................... 12-26

Inner Tube Inspection .................. 12-29

Guide Bush Inspection................. 12-30

Dust Seal/Oil Seal Inspection ...... 12-30

Spring Tension ............................. 12-30

Rear Suspension (Uni-Trak).............. 12-31

Rear Shock Absorber: .................... 12-31

Rebound Damping Adjustment .... 12-31

Compression Damping

Adjustment ................................ 12-32

Spring Preload Adjustment .......... 12-32

Spring Tension ............................. 12-33

Rear Shock Absorber Removal ... 12-33

Rear Shock Absorber Installation 12-34

Spring Replacement .................... 12-34

Rear Shock Absorber

Disassembly (Oil C hange) ........ 12-35

Rear Shock Absorber Assembly .. 12-37

Rear Shock Absorber Scrapping . 12-40

Swingarm........................................... 12-41

Swingarm Removal...................... 12-41

Swingarm Installation................... 12-41

Swingarm Bearing Removal ........ 12-42

Swingarm Bearing Installation ..... 12-42

Drive Chain Guide, Chain Slipper

Wear.......................................... 12-42

Tie-Rod, Rocker Arm......................... 12-43

Tie-Rod Removal ......................... 12-43

Tie-Rod Installation ...................... 12-43

Rocker Arm Removal................... 12-43

Rocker Arm Installation................ 12-44

Tie-Rod and Rocker Arm Bearing

Removal.................................... 12-44

Tie-Rod and Rocker Arm Bearing

Installation................................. 12-45

Needle Bearing Inspection........... 12-45

Uni-Trak Maintenance ....................... 12-46

Uni-Trak Linkage Inspection ........ 12-46

Rocker Arm Sleeve Wear ............ 12-46

Rocker Arm Mounting Bolt Bend.. 12-46

12-2 SUSPENSION

Exploded View

KX125/250-M1:

SUSPENSION 12-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Front Fork Top Plug 29 3.0 22

2 Front Fork Clamp Bolts (Upper, Lower) 20 2.0 14.5

3 Steering Stem Head Nut 78 8.0 58

4 Push Rod Nut 28 2.9 21

5 Front Axle Clump Bolts 20 2.0 14.5

6 Front Fork Cylinder Valve Assembly 54 5.5 40 L

7. Screw

8. O-Ring

9. Damper

10. Washer

11. Spring Seat

12. Spring

13. Rebound Damping Adjuster Rod

14. Spring Guide

15. Push Rod

16. Fork Cylinder

17. Outer Tube

18. Guide Bush

19. Washer

20. Oil Seal

21. Retaining Ring

22. Dust Seal

23. Inner Tube

24. Gasket

25. Cap

26. Steering Stem Head

27. Steering Stem

28. Fork Guide

29. Fork Protector

L: Apply a non-permanent locking agent to the threads.

12-4 SUSPENSION

Exploded View

KX125/250-M2∼

SUSPENSION 12-5

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Front Fork Top Plug 29 3.0 22

2 Front Fork Clamp Bolts (Upper, Lower) 20 2.0 14.5

3 Steering Stem Head Nut 78 8.0 58

4 Push Rod Nut 28 2.9 21

5 Front Axle Clump Bolts 20 2.0 14.5

6 Front Fork Cylinder Valve Assembly 54 5.5 40 L

7. Screw

8. O-ring

9. Spring Seat

10. Spring

11. Rebound Damping Adjuster Rod

12. Spring Guide

13. Push Rod

14. O-ring

15. Guide Stay Nut

16. Snap Ring

17. Stopper

18. Piston Holder

19. Fork Cylinder

20. Outer Tube

21. Fork Guide

22. Guide Bush

23. Washer

24. Oil Seal

25. Retaining Ring

26. Dust Seal

27. Guide Bush

28. Inner Tube

29. Gasket

30. Cap

31. Steering Stem Head

32. Steering Stem

33. Fork Protector

L: Apply a non-permanent locking agent to the threads.

12-6 SUSPENSION

Exploded View

KX125/250-M1:

SUSPENSION 12-7

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Swingarm Pivot Shaft Nut 98 10.0 72

2 Rocker Arm Pivot Nut 83 8.5 61

3 Tie-Rod Mounting Nut (Front, Rear) 83 8.5 61

4 Rear Shock Absorber Mounting Nut (Upper) 39 4.0 29

5 Rear Shock Absorber Mounting Nut (Lower) 34 3.5 25

6. Pivot Shaft

7. Swingarm

8. Rocker Arm

9. Ti e-Rod

10. Rear Shock Absorber Cylinder

11. Bladder

12. Cap

13. Circlip

14. Valve Cap

15. Locknut

16. Adjusting Nut

17. Spring

18. Spring Guide

19. Circlip

20. Piston Rod Assembly

21. Piston

22. O-ring

23. Oil Seal

24. Stopper

25. Rear Shock Absorber

G: Apply grease.

12-8 SUSPENSION

Exploded View

KX125/250-M2∼

SUSPENSION 12-9

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Swingarm Pivot Shaft Nut 98 10.0 72

2 Tie-Rod Mounting Nut (Front, Rear) 83 8.5 61

3 Rocker Arm Pivot Nut 83 8.5 61

4 Rear Shock Absorber Mounting Nut (Upper) 39 4.0 29

5 Rear Shock Absorber Mounting Nut (Lower) 34 3.5 25

6. Pivot Shaft

7. Swingarm

8. Rocker Arm

9. Ti e-Rod

10. Rear Shock Absorber Cylinder

11. Air Bleeder Bolt

12. O-ring

13. Bladder

14. Cap

15. Circlip

16. Valve Cap

17. Locknut

18. Adjusting Nut

19. Spring

20. Spring Guide

21. Circlip

22. Piston Rod Assembly

23. Piston

24. O-ring

25. Oil Seal

26. Stopper

27. Rear Shock Absorber

G: Apply grease.

L: Apply a non-permanent locking agent to the threads.

12-10 SUSPENSION

Specifications

KX125/250-M1:

Item

Standard Service Limit

Front Fork

Air Pressure Atmospheric pressure –––

Rebound Damping Adjustment (Adjustable Range)

(from the seated position adjuster

turned fully clockwise):

13 clicks counterclockwise 16 clicks

Compression Damping Adjustment

(from the seated position adjuster

turned fully clockwise):

(Adjustable Range)

KX125 14 clicks counterclockwise 16 clicks

KX250 13 clicks counterclockwise

Oil Viscosity KHL15-10 (KAYABA 01) or

equivalent

–––

Oil Capacity:

KX125 652±4mL(22.04±0.14USoz.) –––

KX250

664±4mL(22.45±0.14USoz.)

Oil Level (fully compressed, spring

removed):

(Adjustable Range)

KX125

135±2mm(5.31±0.08in.)

100 ∼ 145 mm

(from top of outer tube) (3.94 ∼ 5.71 in.)

KX250 125±2mm(4.92±0.08in.)

(from top of outer tube)

Fork Spring Free Length 460 mm (18.11 in.) 450 mm (17.72 in.)

Rear Suspension (Uni-Trak)

Rear Shock Absorber:

Rebound Damping Adjustment

(from the seated position adjuster

fully clockwise) Turned:

(Adjustable Range)

KX125 12 clicks counterclockwise 16 clicks

KX250 10 clicks counterclockwise

Spring Preload Adjustment

(Adjusting nut position from the

center of the mounting hole upper):

(Adjustable Range)

KX125

112 mm (4.41 in.)

109 ∼ 127.5 mm

(4.29 ∼ 5.02 in.)

KX250 117 mm (4.61 in.) 109 ∼ 129.5 mm

(4.29 ∼ 5.10 in.)

Rear Shock Spring Free Length 260 mm (10.24 in.) 255 mm (10.04 in.)

Gas Reservoir:

Compression Damping Adjustment

(from the seated position adjuster

turned fully clockwise):

(Adjustable Range)

KX125 13 clicks counterclockwise 16 clicks

KX250 12 clicks counterclockwise

Gas Pressure 980 kPa (10 kgf/cm², 142 psi) –––

SUSPENSION 12-11

Specifications

Item Standard Service Limit

Tie-Rod, Rocker Arm:

Sleeve Outside Diameter:

Large 19.987 ∼ 20.000 mm (0.7869 ∼

0.7874 in.)

19.85 mm (0.781 in.)

Small 15.987 ∼ 16.000 mm (0.6294 ∼

0.6299 in.)

15.85 mm (0.624 in.)

Rocker Arm Mounting Bolt Runout under 0.1 mm (0.004 in.) 0.2 mm (0.008 in.)

12-12 SUSPENSION

Specifications

KX125/250-M2 ∼ :

Item

Standard Service Limit

Front Fork

Air Pressure Atmospheric pressure –––

Rebound Damping Adjustment (Adjustable Range)

(from the seated position adjuster

turned fully clockwise):

14 clicks counterclockwise 16 clicks

Compression Damping Adjustment

(from the seated position adjuster

turned fully clockwise):

(Adjustable Range)

KX125 10 clicks counterclockwise 16 clicks

KX250 10 clicks counterclockwise

Oil Viscosity KHL15-10 (KAYABA 01) or

equivalent

–––

Oil Capacity:

KX125 565±4mL(19.10±0.14USoz.) –––

KX250

578±4mL(19.54±0.14USoz.)

–––

Oil Level (fully compressed, spring

removed):

(Adjustable Range)

KX125

105±2mm(4.13±0.08in.)

70 ∼ 120 mm

(from top of outer tube) (2.76 ∼ 4.72 in.)

KX250 88 ±2 mm (3.46 ±0.08 in.)

(from top of outer tube) \

Fork Spring Free Length 460 mm (18.11 in.) 450 mm (17.72 in.)

Rear Suspension (Uni-Trak)

Rear Shock Absorber:

Rebound Damping Adjustment

(from the seated position adjuster

fully clockwise) Turned:

(Adjustable Range)

KX125 11 clicks counterclockwise 16 clicks

KX250 10 clicks counterclockwise

Spring Preload Adjustment

(Adjusting nut position from the

center of the mounting hole upper):

(Adjustable Range)

KX125

111 mm (4.37 in.)

109 ∼ 127.5 mm

(4.29 ∼ 5.02 in.)

KX250 112 mm (4.41 in.) 109 ∼ 129.5 mm

(4.29 ∼ 5.10 in.)

Rear Shock Spring Free Length 260 mm (10.24 in.) 255 mm (10.04 in.)

Gas Reservoir:

Compression Damping Adjustment

(from the seated position adjuster

turned fully clockwise):

(Adjustable Range)

KX125 13 clicks counterclockwise 16 clicks

KX250 10 clicks counterclockwise

Gas Pressure 980 kPa (10 kgf/cm², 142 psi) –––

SUSPENSION 12-13

Specifications

Item Standard Service Limit

Tie-Rod, Rocker Arm

Sleeve Outside Diameter:

Large 19.987 ∼ 20.000 mm (0.7869 ∼

0.7874 in.)

19.85 mm (0.781 in.)

Small 15.987 ∼ 16.000 mm (0.6294 ∼

0.6299 in.)

15.85 mm (0.624 in.)

Rocker Arm Mounting Bolt Runout under 0.1 mm (0.004 in.) 0.2 mm (0.008 in.)

12-14 SUSPENSION

Special Tools

Oil Seal & Bearing Re m over:

57001-1058

Steering Stem Nut Wrench:

57001-1100

Hook Wrench R37. 5, R42:

57001-1101

Bearing Driver Set:

57001-1129

Fork O uter Tube Weight:

57001-1218

Jack:

57001-1238

Bearing Rem o ver Shaft, 9:

57001-1265

Bearing Remover Head, 15 × 17:

57001-1267

Fork Piston Rod Puller, M12 × 1.25:

57001-1289

Fork Oil Level Gauge:

57001-1290

SUSPENSION 12-15

Special Tools

Fork Cylinder Holder:

57001-1413

Fork O il Seal Driver, 48:

57001-1509

Fork Cylinder Holder:

57001-1573

12-16 SUSPENSION

Front Fork

Air Pressure

The standard air pressure in the front fork legs is atmo-

spheric pressure. Air pressure in the fork legs increase

with normal use, so the fork action stiffens during opera-

tion. Release air pressure form the fork legs prior to each

race through the pressure relief screw located in each front

fork cap.

•

Place the jack under the frame so that the front wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Remove the screws [A] at the top of the front fork top plugs

to let the air pressure equalize.

NOTE

○

Do not use the side stand when adjusting the air pres-

sure.

○

Adjust the air pressure when the front forks are cold.

•

Check the O-ring of the s crew. Replace the O-ring with a

new one if damage.

•

Install the screw.

Rebound Damping Adjustment

•

Place the jack under the frame so that the front wheel off

the ground.

Special Tool - Jack: 57001-1238

•

To adjust rebound damping, turn the adjuster [A] on the

front fork top plugs with the blade of a screwdriver until

you feel a click. Adjust the rebound damping to suit you

preference under special condition.

NOTE

○

The left and right fork legs must have the same shock

damping.

Seated positions: adjuster turned fully clockwise [A].

Rebound Damping A djuster Setting

Standard:

KX125-M1: 13 clicks

KX125-M2∼: 14 clicks

KX250-M1: 13 clicks

KX250-M2∼: 14 clicks

SUSPENSION 12-17

Front Fork

Compression Damping Adjustment

•

Place the jack under the frame so that the front wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Clean the bottom of the fork tubes.

•

Remove the on the bottom of the fork tubes.

•

To adjust compression damping, turn the adjuster [A] on

the front fork cylinder valve with the blade of a screwdriver

until you feel a click. Adjust the compression damping to

suit your preference under special condition.

NOTE

○

The left and right fork legs must have the same shock

damping.

Seated positions adjuster turned fully clockwise [A].

•

Put the caps into the bottom of the fork tubes.

Compressio n Damping Adjuster Setting

Standard:

KX125-M1: 14 clicks

KX125-M2∼: 10 clicks

KX250-M1: 13 clicks

KX250-M2 ∼: 10 clicks

Fork Oil Level Adjustment (Simplify)

•

Raise the front wheel off the ground using a jack.

Special Tool - Jack: 57001-1238

•

Remove:

Front Fender

Brake Hose Guard [A]

Brake Hose Clamps [B]

Fork Protectors [C]

Number Plate

Handlebar

•

For KX125/250-M2 model ∼; note the following.

○

Raise the front wheel off the ground using a jack.

Special Tool - Jack: 57001-1238

○

Remove:

Front Fender

Brake Hose Clamps [A]

Fork Protectors [B] and Protector Guides

Number Plate

Handlebar

12-18 SUSPENSION

Front Fork

•

Loosen the upper fork clamp bolts.

•

Disassemble the front fork top plugs from the outer tube.

•

Slowly compress the front fork fully by pushing up the

inner tubes [A] until they are s tepped portion contacts the

dust seals [B] on the lower end of the outer tubes [C].

•

For KX125/250-M2 model ∼; as shown in the figure.

•

Place a stand or other suitable support [A] under the front

wheel.

•

For KX125/250-M2 model ∼; as shown in the figure.

•

While holding the push rod nut with a 17 mm (0.67 in.)

wrench [A], loosen the front fork top plug [B] from the top

of the push rod.

•

Remove the fork top plug with the fork spring s eat [C] and

fork spring [D].

•

Remove the other fork spring in the same way as de-

scribed above.

SUSPENSION 12-19

Front Fork

•

For KX125/250-M2 model; note the following.

○

While holding the push rod nut with a 19 mm (0.75 in.)

wrench [A], loosen the front fork top plug [B] from the top

of the push rod.

○

Remove the fork top plug with the fork spring seat [C] and

fork spring [D].

○

Remove the other fork spring in the same way as de-

scribed above.

•

Use the oil level gauge to measure the fork oil level.

○

With the fork fully compressed, put the oil level gauge [A]

and the stopper [B], and adjust the distance from the top

of the inner tube to oil.

Special Tool - Fork Oil Level Gauge: 57001-1290

Front Fork Oil Level (fully compressed, without spring)

Standard:

KX125-M1:

133 ∼ 137 mm (5.24 ∼ 5.39 in.)

KX125-M2 ∼:

103 ∼ 107 mm (4.00 ∼ 4.21 in.)

KX250-M1:

123 ∼ 127 mm (4.84 ∼ 5.00 in.)

KX250-M2 ∼:

86 ∼ 90 m m (3.39 ∼ 3.54 in.)

Adjustable Range:

KX125/250-M1: 100 ∼ 145 mm (3.94 ∼ 5.71 in.)

KX125/250-M2 ∼:70∼ 120 mm (2.76 ∼ 4.72 in.)

If no oil is drawn out, there is insufficient oil in the fork

tube. Pour in enough oil, then pump out the excess oil.

Recommended Fork Oil: KHL15-10 (KAYABA 01) or

equivalent

•

Install the push rod puller [A] onto the push rod [B].

•

Slowly pull up the push rod.

•

Let the fork oil overflow through the hole in the push rod

until it stops.

•

Insert the fork spring [A] into the fork tube.

•

Remove the push rod puller.

12-20 SUSPENSION

Front Fork

•

Install the fork spring seat [A] on the fork spring [B].

•

Check both top plug O-ring [C] for damage and replace

them if necessary.

•

For KX125/250-M2 model ∼; as shown in the figure.

•

While holding the push rod nut [A] with a 17 mm (0.67 in.)

wrench [B], tighten the top plug [C] against the push rod.

•

For KX125/250-M2 model ∼; while holding the push rod

nut [A] with a 19 mm (0.75 in.) wrench [B], tighten the top

plug [C] against the push rod.

•

Tighten the fork top plug.

Torque - Push Rod Nut: 28 N·m (2.9 kgf·m, 21 ft·lb)

Front Fork Top Plug: 29 N·m (3.0 kgf·m, 22 ft·lb)

•

Assemble the other fork tube in the same way as de-

scribed above.

•

Tighten the upper fork clamp bolts.

Torque - Front Fork C lamp Blots (Upper): 20 N·m (2.0

kgf·m, 14.5 ft·lb)

NOTE

○

Tighten the two clamp bolts alternately two times to en-

sure even tightening torque.

•

Install the parts removed.

SUSPENSION 12-21

Front Fork

Oil Change/Oil Level Adjustment (each fork leg)

•

Refer to the Front Fork Oil Change/Oil Level Adjustment

in the Periodic Maintenance chapter.

Front Fork Removal

•

Remove the fork protectors [A] and hose guard [B].

•

Remove the front brake hose clamps [C].

•

Remove the front wheel (see Wheels/Tires chapter).

•

Remove the caliper [D] from the fork leg to be removed,

and rest the caliper on some kind of stand so that it doesn’t

dangle.

•

For KX125/250-M2 model; note the following.

○

Remove the fork protectors [A].

○

Remove the front brake hose clamps [B].

○

Remove the front wheel (see Wheels/Tires chapter).

○

Remove the caliper [C] from the fork leg to be removed,

and rest the caliper on some kind of stand so that it doesn’t

dangle.

•

Remove the number plate.

•

Loosen the upper and lower fork clamp bolts [A].

•

With a twisting motion, work the fork leg down and out.

Front Fork Installation

•

If the fork leg was disassembled, check the fork oil level.

•

Install the fork so that the distance [B] between the top

end [A] of the outer tube and the upper surface [C] of the

steering stem head is specified dimension.

[B] = 15 mm (0.59 in.)

•

Route the cables and hose according to the Cable, Har-

ness, Hose Routing section in the Appendix chapter.

•

Install the front wheel (see Wheels/Tires chapter).

•

Tighten the fork clamp bolts.

Torque - Front Fork Clamp Bolts (Upper, Lower): 20 N·m

(2.0 kgf·m, 14.5 ft·lb)

NOTE

○

Tighten the two clamp bolts alternately two times to en-

sure even tightening torque.

•

Tighten:

Torque - Front Caliper Mounting Bolts: 25 N·m (2.5 kgf·m,

18 ft·lb)

•

Check the front brake operation after installation.

12-22 SUSPENSION

Front Fork

Front Fork Disassembly (each fork leg)

Spring Guide Removal

•

Place the handlebar on one side, and loosen the each

fork top plug.

•

Remove the front fork.

•

Hold the inner tube lower end in a vise.

•

Disassemble the top plug from the outer tube.

•

Push the outer tube all the way down away from the top

plug and hold it there through out the following procedure.

○

For KX125/250-M1 model, pull the fork spring [A] away

from the top plug a little and sip the spanner wrench [B] in

on top of the spring seat and under the push rod nut [C].

•

Use wrenches on the rod nut and top plug [A] loosen the

push rod nut.

•

Remove the top plug from the push rod.

•

Lift the fork spring [B] and its top spring seat [C] out of the

outer tube.

•

For KX125/250-M2 model ∼; as shown in the figure.

•

Take the rebound damping adjuster rod [A] out of the push

rod.

SUSPENSION 12-23

Front Fork

•

Hold the fork tube [A] upside down over a clean container

[B] and pump it to drain the oil.

NOTE

○

To discharge the fork oil, pump the push rod up [C] and

down ten times.

•

Remove the push rod nut [A] and the spring guide [B].

Cylinder Unit Removal (KX125/250-M1)

•

Clean the bottom of the inner tube.

•

Remove the cap on the bottom of the inner tube.

•

Hold the front fork horizontally in a vise.

•

Stop the cylinder unit [A] from turning by using the fork

cylinder holder [B]. Unscrew the cylinder valve assembly

[C], and take the cylinder valve assembly and gasket out

of the bottom of the inner tube.

Special Tool - Fork Cylinder Holder: 57001-1413

A. Inner Tube

B. Cylinder Valve Assembly

C. O-ring

D. Gasket

•

Pull the cylinder unit [A] out the top of the inner tube.

NOTE

○

Do not disassembly the cylinder unit as the push rod

and cylinder are consisted of as the single assembly.

12-24 SUSPENSION

Front Fork

Cylinder Unit Removal (KX125/250-M2 ∼)

•

Using the spanner wrench [A], loosen the guide stay nut

[B].

•

Remove the snap ring [A].

•

Remove the O-ring [B], the guide stay nut [C], the stopper

[D] and the piston holder [E].

•

Clean the bottom of the inner tube.

•

Remove the cap on the bottom of the inner tube.

•

Hold he front fork horizontally in a vise.

•

Stop the cylinder unit [A] from turning by using the fork

cylinder holder [B]. Unscrew the cylinder valve assembly

[C], and take the cylinder valve assembly and gasket out

of the bottom of the inner tube.

Special Tool - Fork Cylinder Holder: 57001-1573

A. Inner Tube

B. Cylinder Valve Assembly

C. O-ring

D. Gasket

•

Pull the cylinder unit [A] out the top of the inner tube [B].

SUSPENSION 12-25

Front Fork

CAUTION

Do not disassemble the air chamber [A] by remov-

ing the spring [B] because the sealed air into the

cylinder unit may be leaked.

•

Pull the push rod assembly out the bottom of the cylinder

unit.

Inner Tube Removal

•

Separate the inner tube [A] from the outer tube [B] as

follows:

○

Slide up the spring band [C].

○

Slideupthedustseal[D].

○

Remove the retaining ring [A] from the outer tube.

○

Grasp the outer tube and stroke the inner tube up and

down several times. The shock to fork seal separates the

inner tube from the outer tube.

If the tubes are tight, use a fork outer tube weight [A].

Special Tool - Fork Outer Tube Weight: 57001-1218

12-26 SUSPENSION

Front Fork

•

Remove the guide bushes [A], washer [B], oil s eal [C],

retaining ring [D], and dust seal [E] from the inner tube.

•

For KX125/250-M2 model ∼; remove the guide bushes

[A], collar [B], oil seal [C], retaining ring [D], and dust seal

[E] from the inner tube.

Front Fork Assembly

Inner to Outer Tube Assembly

•

Replace the following with new ones:

Dust Seal [A]

Retaining Ring [B]

Oil Seal [C]

Guide Bushes [D]

•

Place an oil coated plastic bag [E] over the end of the

inner tube to protect the oil seals.

○

The inner tube guide bush groove has a sharp edge [F]

that can out the sealing lip of the seals as they are pushed

down over the inner tube.

•

Install in order these parts on the inner tube.

•

When assembling the new outer tube guide bush [A], hold

the washer against the new one, and tap the washer with

the fork oil seal driver [B] until it stops.

Special Tool - Fork Oil Seal Driver, 48: 57001-1509

•

After installing the washer, install the oil seal by using the

fork oil seal driver.

Special Tool - Fork Oil Seal Driver, 48: 57001-1509

•

Install the retaining ring to the outer tube.

•

Push the dust seal into the outer tube, and put the s pring

band on the dust seal.

SUSPENSION 12-27

Front Fork

Install Inner Cylinder (KX125/250-M1)

•

Install the cylinder unit.

•

Check the O-ring [A] on the cylinder valve assembly [B],

and replace it with a new one.

•

Replace the gasket [C] with a new one.

•

Apply a non-permanent locking agent to the threads [D] of

the cylinder valve assembly and screw the valve assem-

bly into the bottom of the inner tube.

•

Hold the cylinder unit with the fork cylinder holder, and

tighten the cylinder valve assembly.

Special Tool - Fork Cylinder Holder: 57001-1413

Torque - Cylinder Valve Assembly: 54 N·m (5.5 kgf·m, 40

ft·lb)

Install Inner Cylinder (KX125/250-M2∼)

•

Install the cylinder unit.

•

Check the O-ring [A] on the cylinder valve assembly [B],

and replace it with a new one.

•

Replace the gasket [C] with a new one.

•

Apply a non-permanent locking agent to the threads [D] of

the cylinder valve assembly and screw the valve assem-

bly into the bottom of the inner tube.

•

Hold the cylinder unit with the fork cylinder holder, and

tighten the cylinder valve assembly.

Special Tool - Fork Cylinder Holder: 57001-1573

Torque - Cylinder Valve Assembly: 54 N·m (5.5 kgf·m, 40

ft·lb)

•

Check the O-ring [A] on the guide stay nut, and replace it

with a new one if damaged.

•

Install the inner cylinder unit.

•

Install the piston holder [A] into the push rod assembly

[B], then the stopper [C], so that its notch side downward

to the piston holder.

•

Install the snap ring [D] in the groove of the push rod as-

sembly.

•

Fastening the top end of the piston holder to the snap ring

and tighten the guide stay nut [E] to the piston holder.

Torque - Guide Stay Nut: 27 N·m (2.8 kgf·m, 20 ft·lb)

NOTE

○

Be sure to install securely a snap ring to fasten the stop-

per on the push rod.

○

If it is not securely installed, the fork may be damaged.

12-28 SUSPENSION

Front Fork

•

Install the spring guide [A] so that the thinner portion end

[B] is down.

•

Screw on the push rod nut [C] fully.

•

For KX125/250-M2 ∼; as shown in the figure.

•

Insert the rebound damping adjuster rod [A] into the push

rod.

•

Pour in the type and amount of fork oil specified and adjust

the oil level (see Oil Level Adjustment).

•

Screw the fork piston rod puller [A] onto the end of the

push rod.

Special Tool - Fork Piston Rod Puller, M12 x 1.25: 57001

-1289

•

Pull the push rod up with the special tool for the next pro-

cedures.

○

Pull up the push rod slowly so as not to spill the fork oil

out of the fork tube.

•

Install the fork spring [A].

•

Pull the fork spring away a little and slip the fork spring

holder in on top of the spring seat and under the push rod

nut .

SUSPENSION 12-29

Front Fork

•

Remove the fork piston rod puller.

•

Check the O-ring [A] on the top plug and replace it with a

new one if damaged.

•

Unscrew the rebound damping adjuster fully, then screw

the front fork top plug onto the push rod.

•

Holding the top plug [B] with a wrench, tighten the push

rod nut [C] against the top plug.

Torque - Push Rod Nut: 28 N·m (2.9 kgf·m, 21 ft·lb)

•

For KX125/250-M2 model∼; as shown in the figure.

•

Pull out the fork spring holder, raise the outer tube and

screwthetopplugintoit.

•

After installing the front fork, tighten the top plug.

Torque - Fork Top Plug: 29 N·m (3.0 kgf·m, 22 ft·lb)

Inner Tube Inspection

•

Visually inspect the inner tube [A], repair any damage.

•

Nick or rust damage can sometimes be repaired by using

a wet-stone to remove sharp edges or raised areas which

cause seal damage.

If the damage is not repairable, replace the inner tube.

Since damage to the inner tube damages the oil seal,

replace the oil seal whenever the i nner tube is repaired

or replaced.

•

Temporarily assemble the inner and outer tubes, and

pump them back and forth manually to check for smooth

operation.

CAUTION

If the inner tube is badly bent or creased, replace

it. Excessive bending, followed by subsequent

straightening, can weaken the inner tube.

12-30 SUSPENSION

Front Fork

Guide Bush Inspection

•

Visually inspect the guide bushes [A], and replace them if

necessary.

Dust Seal/Oil Seal Inspection

•

Inspect the dust seal [A] for any signs of deterioration or

damage.

Replace it if necessary.

•

Replace the oil seal [B] with a new one whenever it has

been removed.

Spring Tension

•

Since a spring becomes shorter as it weakens, check its

free length [A] to determine its condition.

If the spring of either fork leg is shorter than the service

limit, it must be replaced. If the length o f a replacement

spring and that of the remaining spring vary greatly, the

remaining spring should also be replaced in order to keep

the fork legs balanced from motorcycle stability.

Fork Spring Free Length

Standard: 460 mm (18.11 in.)

Service Limit: 450 mm ( 17.72 in.)

SUSPENSION 12-31

Rear Suspension (Uni-Trak)

Rear Shock Absorber:

The rear suspension system of this motorcycle is Uni-trak.

It consists of a rear shock absorber, swing arm, tie-rod and

rocker arm.

To suit to various riding conditions, the spring preload of

the shock absorber can be adjusted or the spring can be

replaced with an optional one. Also the damping force can

be adjusted easily so changing oil viscosity unnecessary.

Rebound Damping Adjustment

•

Turn the rebound damping adjuster [A] on the rear shock

absorber lower end with the blade of a screwdriver until

you feel a click.

If the damper setting feels too soft or too stiff, adjust it in

accordance with the following table:

•

For KX125/250-M2 model∼; as shown in the figure.

[A]: Rebound Damping Adjuster

Seated position: adjuster turned fully clockwise [A].

Rebound Damping Adjuster Setting

Standard:

KX125-M1: 12 clicks

KX125-M2∼:11clicks

KX250: 10 clicks

NOTE

○

Adjustment of the rebound damping adjuster for the rear

suspension will slightly affect the compression damping

force. Always make any damping adjustments in small

steps and test their effects before using them in com-

petition.

12-32 SUSPENSION

Rear Suspension (Uni-Trak)

Compression Damping Adjustment

•

Turn the compression damping adjuster [A] on the rear

shock absorber gas reservoir with a flat-bead screwdriver.

If the damping feels too soft or too stiff, adjust it in accor-

dance with the following table.

Seated position: adjuster turned fully clockwise [A].

Compression Damping

Standard:

KX125: 13 clicks

KX250-M1: 12 clicks

KX250-M2∼:10clicks

NOTE

○

Adjustment of the rebound damping adjuster for the rear

suspension will slightly affect the compression damping

force. Always make any damping adjustments in small

steps and test their effects before using them in com-

petition.

Spring Preload Adjustmen t

•

Remove:

Seat

Side Covers

Muffler

Rear Frame M ounting Bolts [A]

Rear Frame [B] with Air Cleaner Housing

•

Using the jack under the frame, raise the rear wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Using the hook wrenches [A], loosen the locknut [B] on

the rear shock absorber.

Special Tool - Hook Wrench R37.5, R42: 57001-1101

SUSPENSION 12-33

Rear Suspension (Uni-Trak)

•

Using the stem nut wrench [A], turn the adjusting nut [B]

as required. Turning the adjusting nut downward marks

the spring action harder and upward softer.

Special Tool - Steering Stem N ut Wrench: 57001-1100

Spring Preload Adjustment

(Adjusting nut position [A] from the center of the

mounting hole)

Standard:

KX125-M1:

112 mm (4.41 in.)

KX125-M2∼:

111 mm (4.37 in.)

KX250-M1:

117 mm (4.61 in.)

KX250-M2∼:

112 mm (4.41 in.)

Adjustable Range

KX125:

109 ∼ 127.5 mm (4.29 ∼ 5.02 in.)

KX250:

109 ∼ 129.5 mm (4.29 ∼ 5.10 in.)

•

Tighten the locknut securely.

•

After adjusting, move the spring up and down to make

sure that the spring is seated.

•

Install the parts removed.

•

Tighten the rear frame mounting bolts.

Torque - Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m 25

ft·lb)

Spring Tension

•

Since the spring becomes shorter as it weakens, check

its free length [A] to determine its condition.

If the spring of either rear shock absorber is shorter than

the service limit, it must be replaced. If the length of re-

placement spring and that of the remaining spring vary

greatly, the remaining spring should also be replaced in

order to keep the rear shock absorbers balanced of mo-

torcycle stability.

Shock Absorber Spring Free Length

Standard: 260 mm (10.24 in.)

Service Limit: 255 mm (10.04 in.)

Rear Shock Absorb er Removal

•

Remove:

Seat

Side Covers

Muffler

Rear Frame with Air Cleaner Housing

•

Using the jack under the frame, raise the rear wheel off

the ground.

Special Tool - Jack: 57001-1238

12-34 SUSPENSION

Rear Suspension (Uni-Trak)

•

Remove the tie-rod front mounting bolt [A].

CAUTION

When pulling out the mounting bolts, lift the rear

wheel slightly. Forcing or tapping on a bolt could

damage the bolt, sleeve, and bearing

•

Remove the rear shock absorber lower mounting bolt [B].

•

For KX125/250-M2 model∼; note the following.

○

Remove the tie-rod rear mounting bolt [A].

○

Remove the rear shock absorber lower mounting bolt [B].

•

Remove the rear shock absorber upper mounting bolt [A],

nut, and pull out the rear shock absorber [B] down and

out.

Rear Shock Absorber Installation

•

Pack the rocker arm needle bearings with grease.

•

Tighten the following:

Torque - Rear Shock Absorber Mounting Nut (Upper): 39

N·m (4.0 k gf·m, 2 9 ft·lb)

Rear Shock Absorber Mounting Nut (Lower): 34

N·m (3.5 k gf·m, 2 4 ft·lb)

Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

Rear Frame Mounting Bolts: 34 N·m (3.5 kgf·m, 25

ft·lb)

Spring Replacement

In addition to the standard spring, heavy and light springs

are available. If the standard spring is improper for your

purpose, select a proper one according to the rider’s weight

or course conditions.

•

Remove

Side Covers

Seat

Muffler

Rear Frame with Air Cleaner Housing

•

Remove the rear shock absorber.

•

Clean the threaded portion on the upper of the rear shock

absorber.

•

Hold the lower of the rear shock absorber with a vise.

SUSPENSION 12-35

Rear Suspension (Uni-Trak)

•

Using the hook wrenches [C], loosen the locknut [B] and

turn the adjusting nut [A] all way up.

Special Tool - Hook Wrench R37.5, R42: 57001-1101

•

Remove the rear shock absorber from the vise.

•

Slide down the rubber bumper [A].

•

Remove the spring guide [B] from the shock absorber and

lift off the spring [C].

•

Exchange the spring for an optional part. Install the spring

so that closed coil large diameter end [A] faces upward.

•

Install the spring guide.

•

Adjust the spring preload (see Spring Preload Adjust-

ment).

•

Install the rear shock absorber.

•

Install the parts removed.

Rear Shock Absorber Disassembly (Oil Change)

The oil should be changed in the rear shock absorber at

least once per racing season. The frequency for best per-

formance must be based upon riding conditions and rider

ability.

•

Remove the rear shock absorber from the frame (see

Rear Shock Absorber Removal).

•

Remove the shock absorber spring (see Spring Replace-

ment).

•

Point the valve [A] away from you. slowly release nitrogen

gas pressure by pushing down the valve core with a screw

driver.

WARNING

Do not to point the reservoir valve toward your face

or body when releasing nitrogen gas pressure. An

oil mist is often released with the nitrogen. Always

release nitrogen gas pressure before disassem-

bling the rear shock absorber to prevent explosive

separation of parts.

12-36 SUSPENSION

Rear Suspension (Uni-Trak)

•

For KX125/250-M2 model∼; note the following.

○

Adjust the gas reservoir damping adjusters [A] to the soft-

est position.

○

Remove the air bleeder bolt [B] and pump the rear shock

to drain the oil out of the rear shock body.

○

Install the air bleeder bolt.

•

Using the suitable tool [A] and press, push the reservoir

cap [B] in 10 mm (0.39 in.).

•

Remove the circlip [C] from the gas reservoir.

•

Pull the gas reservoir cap [B] out of the gas reservoir using

the pliers [A].

•

Pry or tap [A] at the gaps [B] in the stop [C] with suitable

tools to free the stop from the rear shock body [D].

•

Slide the stop up the top of the piston rod then lightly tap

around the seal with a suitable rod and mallet, and push

the seal assembly 10 mm (0.39 in.) down.

•

Remove the circlip [A].

•

Lightly move the piston rod back and forth, and pull out

the piston rod assembly.

•

Pour the oil out of the rear shock body.

SUSPENSION 12-37

Rear Suspension (Uni-Trak)

Rear Shock Absorber Assembly

•

Pour KYB K2-C (SAE 5W or Bel-Ray SE2 #40) oil into the

gas reservoir to 60 ∼ 70 mm (2.63 ∼ 2.76 in.) [A] from the

gas reservoir upper end.

•

Check that the bladder [A] on the gas reservoir cap is not

partially collapsed.

If it is, push down the valve core with a screwdriver.

•

Check the bladder for s ign of damage or crack.

If necessary, replace it with a new one.

CAUTION

Do not use a damaged or partially collapsed blad-

der, because it may burst, gently reducing rear

shock performance. .

•

Apply grease to the lip [B] of the bladder and install the

reservoir cap [C].

•

Push the bladder into the gas reservoir slowly until it just

clears the circlip groove. Wipe out any spilled oil.

CAUTION

Ensure that no air remains in the system.

•

Check the circlip for weakening, deformity and flaws.

If necessary, replace it with a new one.

CAUTION

If weakened, deformed or flawed circlip is used, the

gas reservoir cap may not hold when injecting the

nitrogen gas. This would allow oil and internal parts

to explode out of the reservoir.

•

Mount the circlip [A] in the groove in the gas reservoir.

12-38 SUSPENSION

Rear Suspension (Uni-Trak)

•

Pull up the gas reservoir cap [A] against the circlip. The

end of the gas reservoir cap must align [C] with the end

of the gas reservoir [B].

WARNING

If the end of the gas reservoir cap and the end of

the gas reservoir are not aligned, the circlip is not

correctly fitting in the groove in the gas reservoir or

is deformed. In this case, the oil and internal parts

could explode out of the reservoir when injecting

the nitrogen gas or while riding the motorcycle.

•

Pour KYB K2-C (SAE 5W or Bel-Ray SE2 #40) oil into the

rear shock body to 55 mm (1.77 in.) [A] from the lower end

[B] of the rear shock body.

•

Insert the piston end [A] of the piston rod assembly into

the rear shock body [C] slowly. Do not insert the seal

assembly [B] yet. Pump the piston rod until all the air is

forced out of the rear shock body.

SUSPENSION 12-39

Rear Suspension (Uni-Trak)

•

Push the seal assembly into the rear shock body until it

just clears the circlip groove.

•

Check the circlip.

If it is deformed or damaged, replace it with a new one.

•

Fit the circlip [A] into the groove in the rear shock body

[B].

CAUTION

If the circlip is not a certain fit in the groove in the

rear shock body, the piston rod assembly may come

out of the shock absorber when injecting the nitro-

gen gas or riding the motorcycle.

•

Pull up the piston rod assembly [C] against the circlip.

•

Force the stop [D] into the rear shock body by lightly tap-

ping around the edge of the stop with a mallet.

•

Fully extend the piston rod assembly.

•

For KX125/250-M2 model∼; note the following.

○

Hold the lower end of the push rod assembly with a vise.

○

Pump the rear shock up and down several times, and then

leave it in the fully extend position for about three minutes.

○

Remove the air bleeder bolt from the upper part of the

rear shock body.

If oil comes out of the air bleeder bolt hole, let it overflow

until it stops.

○

Install the suitable oil cup [A] to the air bleeder bolt hole,

and fill the specified oil into the cup.

○

Purge the air from between the gas reservoir [B] and rear

shock body [C] by slowly pumping the piston rod [D] in

and out.

○

Install the air bleeder bolt securely.

○

Fully extend the piston rod assembly.

•

Inject nitrogen gas to a pressure of 50 kPa (0.5 kgf/cm²,

7 psi) through the valve on the gas reservoir.

•

Check the rear shock body and gas reservoir for oil and

gas leaks.

If there are no leaks, inject the nitrogen gas up to the 980

kPa (10 kgf/cm², 142 psi) pressure.

WARNING

Pressurize the gas reservoir with nitrogen gas only.

Do not use air or other gases, since they may cause

premature wear, rust, fire hazard or substandard

performance.

High pressure gas is dangerous. Have a qualified

mechanic perform this procedure.

•

Install the spring and spring guide.

•

Adjust spring preload. Reinstall the rear shock absorber.

•

Install the parts removed.

12-40 SUSPENSION

Rear Suspension (Uni-Trak)

Rear Shock Absorber Scrapping

WARNING

Since the r eservoir tank of the rear shock absorber

contains nitrogen gas, do not incinerate the reser-

voir tank without first releasing the gas or it may

explode.

•

Remove the shock absorber (see Rear Shock Absorber

Removal).

•

Remove the valve cap [A] and release the nitrogen gas

completely from the gas reservoir.

•

Remove the valve.

WARNING

Since the high pressure gas is dangerous, do not

point the valve toward your face or body.

SUSPENSION 12-41

Swingarm

Swingarm Removal

•

Place the jack under the frame so that the rear wheel is

off the ground.

Special Tool - Jack: 57001-1238

•

Remove:

Rear Wheel (see Wheels/Tires chapter)

Clamps [A]

Brake Pedal [B]

Tie-rod Rear Mounting Bolt [C]

Rear Shock Absorber [D] (see Rear Shock A bsorber Re-

moval)

•

For KX125/250-M2 model∼; note the following.

○

Remove:

Rear Wheel (see Wheels/Tires chapter)

Rear Flap [A]

Clamps [B]

Brake Pedal [C]

Plug and Rocker Arm Pivot Nut [D]

CAUTION

When pulling out the mounting bolts, lift the rear

wheel slightly. Forcing or tapping on a bolt could

damage the bolt, sleeve, and bearing.

•

Pull out the swing arm pivot shaft [E], and remove the

swing arm [F].

•

Separate the chain guide and chain slipper from the swing

arm.

Swingarm Installation

•

Apply plenty of grease to the inside of the needle bear-

ings, sleeves, and oil seals.

•

Tighten the following:

Torque - Swingarm Pivot S haft Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

•

Refer to the Wheels/Tires, Final Drive, and Brakes chap-

ters for wheel installing.

12-42 SUSPENSION

Swingarm

Swingarm Bearing Removal

•

Remove:

Swingarm

Collars [A]

Grease Seals [B]

Sleeves [C]

Needle Bearings [D]

•

Remove the needle bearings using the oil seal & bearing

remove [E].

Special Tool - Oil Seal & Bearing Remover: 57001-1058

•

For KX125/250-M2 model∼; as shown in the figure.

Swingarm Bearing Installation

•

Replace the needle bearings, grease seals and oil seals

with new ones.

•

Apply plenty of grease to the grease seals, oil seals and

needle bearings.

NOTE

○

Install the needle bearings so that the manufacturer’s

marks face out.

○

Install the grease seals so that the deep groove side of

the rip in-ward.

Special Tool - Bearin g Driver Set: 57001-1129

•

Install the needle bearings [A] grease seals [B] and oil

seals [C] position as shown.

○

The installation procedure is the same as the counter

side.

•

For KX125/250-M2 model∼; as shown in the figure.

Drive Chain Guide, Chain Slipper Wear

•

Refer to the Chain G uide and Chain Slipper Wear Inspec-

tion in the Periodic Maintenance chapter.

SUSPENSION 12-43

Tie-Rod, Rocker Arm

Tie-Rod Removal

•

Using the jack under the frame, raise the rear wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Remove the tie-rod front mounting bolt [A].

CAUTION

When pulling out the mounting bolts, lift the rear

wheel slightly. Forcing or tapping on a bolt could

damage the bolt, sleeve, and bearing.

•

Remove the tie-rod rear mounting bolt [B], and then take

out the tie-rods [C].

•

For KX125/250-M2 model∼; note the following.

○

Remove the tie-rod rear mounting bolt [A].

○

Remove the tie-rod front mounting bolt [B], and then take

out tie-rod [C].

Tie-Rod Installation

•

Apply plenty of grease to the inside of the needle bearings

and oil seals.

•

Be sure seated the washers to the rocker arm mating sur-

faces.

•

Tighten the tie-rod front and rear mounting nuts.

Torque - Tie-Rod Mounting Nuts: 83 N·m (8.5 kgf·m, 61

ft·lb)

Rocker Arm Removal

•

Using the jack under the frame, raise the rear wheel off

the ground.

Special Tool - Jack: 57001-1238

•

Loosen the swingarm pivot shaft nut.

•

Remove the tie-rod front mounting bolt [A].

CAUTION

When pulling out the mounting bolts, lift the rear

wheel slightly. Forcing or tapping on bolt could

damage the bolt, sleeve, and bearing.

•

Remove the rear shock absorber lower mounting bolt [B].

•

Remove the rocker arm pivot shaft [C].

•

Remove the rocker arm [D].

12-44 SUSPENSION

Tie-Rod, Rocker Arm

•

For KX125/250-M2 model∼; note the following.

○

Remove the tie-rod rear mounting bolt [A].

○

Remove the rear shock absorber lower mounting bolt [B].

○

Remove the rocker arm pivot shaft [C] and then remove

rocker arm [D].

Rocker Arm Installation

•

Apply plenty of grease to the inside of the rocker arm

holes, needle bearings, oil seals and grease seals out-

side of the sleeve.

•

Be sure seated washers.

•

Tighten the following:

Torque - Rocker Arm Pivot Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

Rear Shock Absorber Mounting Nut (Lower): 34

N·m (3.5 k gf·m, 2 4 ft·lb)

Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

Tie-Rod and Rocker Arm Bearing Removal

•

Remove:

Tie-Rod(seeTie-RodRemoval)

Rocker Arm (see Rocker Arm Removal)

Washers [A]

Sleeves [B]

Oil Seal [C]

Grease Seals [D]

•

Remove the needle bearings [E], using the bearing re-

mover head and bearing remover shaft.

•

Remove the needle bearing [F], using the oil seal & bear-

ing remover.

SUSPENSION 12-45

Tie-Rod, Rocker Arm

Special Tools - Bearing Remover Head, 15 × 17: 57001

-1267

Bearing Remover Shaft,

9: 57001-1265

Oil Seal & Beari ng Remover: 570 0 1-1 05 8

•

For KX125/250-M2∼; as shown in t he figure.

Tie-Rod and Rocker Arm Be aring Installation

•

Replace the needle bearing, grease seals and oil seals

with new ones.

•

Apply plenty of grease to the oil seal and needle bearings.

NOTE

○

Install the grease seals so that the deep groove side of

the rip out-ward.

•

Install the needle bearing [A], [B], grease seals [C] and oil

seals [D] position as shown.

•

Tighten the following:

Torque - Rocker Srm Pivot Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

Rear Shock Absorber Mounting Nut (Lower): 34

N·m (3.5 k g f·m, 24 ft·lb)

Tie-Rod Mounting Nut: 83 N·m (8.5 kgf·m, 61 ft·lb)

Swingarm Pivot Shaft Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

•

For KX125/250-M2 model∼; as shown in the figure.

Needle Bearing Inspection

If there is any doubt as to the condition of either needle

bearing, replace the bearing and sleeve as a set.

12-46 SUSPENSION

Uni-Trak Maintenance

Uni-Trak Linkage Inspection

•

Refer to the Uni-Trak Linkage Inspection in the Periodic

Maintenance chapter.

Rocker Arm Sleeve Wear

•

Pull out the sleeves [A] of the rocker arm, and measure

the outside diameter of the sleeve.

Ifthesleeveiswornpasttheservicelimit,replacethe

sleeve.

Sleeve Outside Diameter

[Large]

Standard: 19.987 ∼ 20.000 mm (0.7869 ∼ 0.7874

in.)

Service Limit: 19 .8 5 mm ( 0. 781 in.)

[Small]

Standard: 15.987 ∼ 16.000 mm (0.6294 ∼ 0.6299

in.)

Service Limit: 15 .8 5 mm ( 0. 624 in.)

Rocker Arm Mounting Bolt Bend

A bent bolt causes vibration, poor handling, and instabil-

ity.

•

To measure the bolt runout, remove the bolt, place it in V

blocks, and set a dial gauge to the bolt at a point halfway

between the blocks. Turn [A] the bolt to measure the

runout. The amount of dial variation is the amount of

runout.

If runout exceeds the service limit, replace the bolt.

Bolt Runout

Standard: Under 0.1 mm (0.004 in.)

Service Limit: 0.2 mm (0.008 in.)

STEERING 13-1

Steering

Table of Contents

Exploded View........................................................................................................................ 13-2

Special Tools .......................................................................................................................... 13-4

Steering .................................................................................................................................. 13-5

Steering Inspection ........................................................................................................... 13-5

Steering Adjustment.......................................................................................................... 13-5

Steering Stem, Stem Bearing Removal ............................................................................ 13-5

Steering Stem, Stem Bearing Installation ......................................................................... 13-6

Steering Maintenance ............................................................................................................. 13-8

Stem Bearing Lubrication.................................................................................................. 13-8

Stem Bearing Wear, Damage ........................................................................................... 13-8

Stem Warp ........................................................................................................................ 13-8

Handlebar............................................................................................................................... 13-9

Handlebar Removal .......................................................................................................... 13-9

Handlebar Installation (KX125-M1 ∼ M3/KX250-M1 ∼ M2)............................................... 13-10

Handlebar Installation (KX125M6F ∼)............................................................................... 13-11

13-2 STEERING

Exploded View

STEERING 13-3

Exploded View

Torque

No. Fastener

N·m kgf·m ft·lb

Remarks

1 Handlebar Clamp Bolts 25 2.5 18.0

2 Steering Stem Head Nut 98 10.0 72

3 Steering Stem Locknut 4.9 0.5 43 in·lb T

Front Fork Clamp Bolts (Upper, Lower)

20 2.0 14.5

5. Handlebar Clamp

6. Handlebar

7. Handlebar Holder

8. Steering Stem Head Bracket

9. Tapered Roller Bearing

10. Head Pipe

11. Tapered Roller Bearing

12. Steering Stem

13. Pad

AD: Apply adhesive cement

G: Apply grease.

O: Apply 2 Stroke Oil

T: Tighten all snugly, then loosen, retighten to 4.9 N·m (0.5 kgf·m, 43 in·lb).

A: KX125-M1 ∼ M3 Model

B: KX125M6F Model ∼

13-4 STEERING

Special Tools

Steering Stem Bearing Driver:

57001-137

Steering Stem Bearin g Driver Adapter, 34.5:

57001-1074

Head Pipe Outer Race Press Shaft:

57001-1075

Head Pipe Outer Race Driver, 51.5:

57001-1076

Head Pipe Outer Race Driver, 54.5:

57001-1077

Steering Stem N ut Wrench:

57001-1100

Head Pipe Outer Race Remo v er I D > 37 mm:

57001-1107

Jack:

57001-1238

STEERING 13-5

Steering

Steering Inspection

•

Refer to the Steering Inspection in the Periodic Mainte-

nance chapter.

Steering Adjustment

•

Refer to the Steering Adjustment in the Periodic Mainte-

nance chapter.

Steering Stem, Stem Bearing Removal

•

Remove:

Front Wheel (see Wheels/Tires chapter)

Brake Hose Clamp (see brake System chapter)

Caliper Mounting Bolts (see Brake System chapter)

Master Cylinder Clamp (see Brake System chapter)

Front Fender

Handlebar (see Handlebar Removal)

Front Fork (see Suspension chapter)

•

Remove the steering stem head nut and washer.

•

Remove the steering stem head.

•

Pushing up on the stem base [A], and remove the steering

stem locknut [B], with the steering stem nut wrench [C],

then remove the steering stem [D] and stem base.

Special Tool - Steering Stem N ut Wrench: 57001-1100

•

Take off the upper stem bearing i nner race (tapered roller

bearing) [A].

•

Drive out the bearing outer races from the head pipe.

○

Remove the outer races pressed into the head pipe, using

the head pipe outer race remover [A], and hammer the

head pipe outer race remover to drive it out.

Special Tool - Head Pipe Outer Race Remover: 57001

-1107

NOTE

○

If either steering stem bearing is damaged, it is recom-

mended that both the upper and lower bearing (includ-

ing outer races) should be replaced with new ones.

13-6 STEERING

Steering

•

Remove the lower stem bearing inner rase (tapered roller

bearing) [A] with its grease seal from the stem using suit-

able tools.

Steering Stem, Stem Bearing Installation

•

Replace the bearing outer race with new ones.

○

Apply grease to the outer races, and drive them into the

head pipe at the same time using the head pipe outer race

press shaft [A] and the drivers.

Special Tools - Head Pipe Outer Race Press Shaft: 57001

-1075

Head Pipe Outer Race D river,

51.5: 57001

-1076 [B]

Head Pipe Outer Race D river,

54.5: 57001

-1077 [C]

•

Replace the lower inner races with new ones.

○

Apply grease to the lower tapered roller bearing [A], and

drive it onto the stem using the steering stem bearing

driver [B] and adapter [C].

Special Tools - Steering Stem Bearing Driver: 57001-137

Steering Stem Beari ng D riv e r Ad ap ter,

34.5: 57001-1074

STEERING 13-7

Steering

•

Apply grease to the upper inner race, and install it in the

head pipe.

•

Install the stem through the head pipe and upper bearing,

install the stem cap and hand-tighten the locknut while

pushing up on the stem base.

•

Install the stem head and washer, and tighten the stem

head nut lightly.

•

Settle the bearing in place as follows;

○

Tighten the stem locknut to 39 N·m (4.0 kgf·m, 29 ft·lb)

of torque. (To tighten the steering s tem locknut to the

specified torque, hook the wrench [A] on the stem locknut,

and pull the wrench at the hole by 22.2 kg force [B] in the

direction shown.)

Special Tool - Steering Stem N ut Wrench: 57001-1100

○

Check that there is no play and the steering stem turns

smoothly without rattles. If not, the steering stem bearings

may be damaged.

○

Again back out the stem locknut a fraction of a turn until

it turns lightly.

○

Turn the stem locknut lightly clockwise until it just be-

comes hard to turn. Do not overtighten, or the steering

will be too tight.

•

Tighten:

Torque - Steering Stem Locknut: 4.9 N·m (0.5 kgf·m, 43

in·lb)

•

Install the front fork (see the Suspension chapter).

NOTE

○

Tighten the fork upper clamp bolts first, next the stem

head nut, last the fork lower clamp bolt.

Torque - Steering Stem Head Nut: 98 N·m (10.0 kgf·m, 72

ft·lb)

Front Fork Clamp Bolts:

Upper: 20 N·m (2.0 kgf·m, 14.5 ft·lb)

Lower : 20 N·m (2.0 kgf·m, 14.5 ft·lb)

NOTE

○

Tighten the two clamp bolts alternately two times to en-

sure even tightening torque.

•

Install the parts removed (see the appropriate chapter).

WARNING

Do not impede the handlebar turning by routing the

cables, wires and hoses improperly (see the Gen-

eral Information chapter).

•

Check and Adjust:

Steering

Front Brake

Clutch Cable

Throttle Cable

13-8 STEERING

Steering Maintenance

Stem Bearing Lubrication

•

Refer to the Stem Bearing Lubrication in the Periodic

Maintenance chapter.

Stem Bearing Wear, Damage

•

Using a high-flash point solvent, wash the upper and

lower tapered rollers in the cages, and wipe the upper

and lower outer races, which are press-fitted into the

frame head pipe, clean off grease and dirt.

•

Visually check the outer rase and the rollers.

Replace the bearing assembly if it show damage.

Stem Warp

•

Whenever the steering stem is removed, or if the steering

cannot be adjusted for smooth action, check the steering

stem for straightness.

If the steering stem shaft is bent [A], replace the steering

stem.

STEERING 13-9

Handlebar

Handlebar Removal

•

Remove:

Clutch Holder [A] (see Clutch chapter)

Engine Stop Switch [B]

Clamp [C] (Discard)

Left Handlebar Grip [D]

•

Remove:

Throttle Grip Assy [A] (see Fuel System chapter)

Master Cylinder [B] (see Brakes chapter)

KX125-M1 ∼ M3/KX250-M1 ∼ M2;

•

Remove:

Handlebar Clamp Bolts [A]

Handlebar Clamp [B]

Handlebar [C]

Number Plate [D]

KX125M6F ∼;

•

Remove:

Number Plate [A]

Pad [B]

•

Remove:

Handlebar Clamp Bolts [A]

Handlebar Clamps [B]

Handlebar [C]

13-10 STEERING

Handlebar

Handlebar Installation (KX125-M1

∼

M3/KX250-M1

∼

M2)

•

Apply adhesive cement to the inside of the left handlebar

grip.

•

Install the left handlebar grip so that the arrow [A] on the

grip point to the punch mark [B] on the handlebar.

•

Install the clutch holder so that the parting line [C] of the

holder with punch mark [D] on the handlebar.

•

Apply grease to the throttle cable upper end and clutch

cable upper end.

•

Apply a 2 stroke engine oil to the throttle grip inner wall

[A].

•

Install the throttle grip assembly so that the grip [A] is in

as far as it will go.

○

Position the throttle grip assembly so that the horizontal

parting line [B] of the throttle case is aligned with punch

mark [C] on the handlebar.

○

Install the master cylinder so that the vertical parting line

[D] of the front master cylinder clamps with punch mark

[E] on the handlebar.

•

Install the handlebar [A] on the handlebar holder as

shown.

Same Length [B]

Bridge Bar [C]

•

Install the handlebar clamp.

○

Mount the handlebar clamp [A] so that the cut side [B] on

the clamp points toward the front.

○

First tighten the rear clamp bolts [C], then, tighten the front

clamp bolts [D]. After tightening the bolts, a clearance will

be created forward the clamp.

•

Tighten the handlebar clamp bolts [C].

Torque - Handlebar Clamp Bolts: 25 N·m (2.5 kgf·m, 18

ft·lb)

STEERING 13-11

Handlebar

Handlebar Installation (KX125M6F

∼

)

•

Apply adhesive cement to the inside of the left handlebar

grip.

•

Install the left handlebar grip and clutch holder as shown.

180 mm (7.09 in.) [A]

Frame Horizontal Line [B]

15° ∼ 25° [C]

20° ∼ 30° [D]

Arrow Mark [E]

Front [F]

•

Apply grease to the throttle cable upper end and clutch

cable upper end.

•

Apply a 2 stroke engine oil to the throttle grip inner wall

[A].

•

Install the throttle grip assembly so that the grip [A] is in

as far as it will go.

185 mm (7.28 in.) [B]

○

Position throttle grip assembly so that the horizontal part-

ing line [C] of the throttle case is parallel the frame hori-

zontal line [D] as shown.

○

Install the master cylinder so that the reserve tank cap

aline [E] to the frame horizontal line as shown.

•

Install the handlebar [A] on the handlebar holder as

shown.

Same Length [B]

Bridge Bar [C]

Protrusion of Graduation [D]

•

Install the handlebar clamps. [A] with handlebar.

○

Tighten the front and rear bolts [B] of the handlebar

clamps equally.

If the handlebar clamps are correctly installed, there will

be same amount of gap [C] on the front and rear side of

the clamp after the bolts tightening.

Torque - Handlebar Clamp Bolts: 25 N·m (2.5 kgf·m, 18

ft·lb)

•

Install:

Pad

Number Plate

ELECTRICAL SYSTEM 14-1

Electrical System

Table of Contents

Wiring Diagram....................................................................................................................... 14-2

Exploded View........................................................................................................................ 14-4

Specifications ......................................................................................................................... 14-6

Special Tools .......................................................................................................................... 14-7

Precautions............................................................................................................................. 14-8

Electrical Wiring...................................................................................................................... 14-9

Wiring Inspection .............................................................................................................. 14-9

Ignition Timing ........................................................................................................................ 14-10

Ignition Timing Adjustment................................................................................................ 14-10

Flywheel Magneto .................................................................................................................. 14-12

Flywheel Magneto Removal .............................................................................................. 14-12

Flywheel Magneto Installation ........................................................................................... 14-13

Flywheel Magneto Inspection ........................................................................................... 14-14

Regulator/Rectifier Removal (KX250)............................................................................... 14-16

Regulator/Rectifier Output Voltage Inspection (KX250).................................................... 14-16

Regulator/Rectifier Inspection (KX250)............................................................................. 14-17

Ignition System ....................................................................................................................... 14-18

Safety Instructions ............................................................................................................ 14-18

Ignition Coil Removal ........................................................................................................ 14-18

Ignition Coil Inspection...................................................................................................... 14-18

Spark Plug Cleaning and Inspection................................................................................. 14-19

Spark Plug Gap Inspection ............................................................................................... 14-19

C.D.I U nit Removal ........................................................................................................... 14-19

C.D.I U nit Inspection ......................................................................................................... 14-20

Throttle Sensor Output/Input Voltage Check: (KX250)..................................................... 14-24

Engine Stop Switch Electric Current Check:..................................................................... 14-24

Crankshaft Sensor Inspection........................................................................................... 14-25

Crankshaft Sensor Air Gap Adjustment ............................................................................ 14-25

Throttle Sensor ....................................................................................................................... 14-26

Throttle Sensor Inspection (KX250).................................................................................. 14-26

Throttle Sensor Position Adjustment (KX250) .................................................................. 14-26

Fuel Cut Valve ........................................................................................................................ 14-27

Fuel Cut Valve Removal (KX250) ..................................................................................... 14-27

Fuel Cut Valve Installation (KX250) .................................................................................. 14-27

Fuel Cut Valve Inspection (KX250) ................................................................................... 14-27

14-2 ELECTRICAL SYSTEM

Wiring Diagram

KX125M:

ELECTRICAL SYSTEM 14-3

Wiring Diagram

KX250M:

14-4 ELECTRICAL SYSTEM

Exploded View

KX125/250:

ELECTRICAL SYSTEM 14-5

Exploded View

Torque

No Fastener

N·m kgf·m ft·lb

Remarks

1 Flywheel Bolt (KX125) 22 2.2 16.0

2 Flywheel Nut (KX250) 78 8.0 58

3 Stator Plate Mounting Screw 4.4 0.45 39 in·lb

Spark Plug

26.5 2.75 19.5

Magneto Cover Bolts (KX125/250-M1) 4.9 0.5 43 in·lb

Magneto Cover Bolts (KX125/250-M2 ∼) 3.9 0.4 35 in·lb

6 C.D.I Unit Mounting Bolts 8.8 0.9 78 in·lb

7 Ignition Coil Mounting Bolts 8.8 0.9 78 in·lb

8. Magneto Cover

9. Flywheel Magneto

10. Stator

11. Ignition Coil

12. C.D.I Unit

13. Spark Plug Cap

14. Main Harness (KX250)

15. Regulator/Rectifier (KX250)

16. Fuel Cut Valve (KX250)

17. Throttle Sensor (KX250)

SS: Apply Silicon Sealant

A: KX125/250-M2 Model ∼

B: KX125-M1 ∼ M2 Model

C: KX125-M3 Model ∼

14-6 ELECTRICAL SYSTEM

Specifications

Item Standard

Magneto

Crankshaft Sensor Air Gap:

KX125-M1 ∼ M6F 0.45 ∼ 0.85 mm (0.018 ∼ 0.033 in.)

KX125M7F ∼ 0.65 ∼ 1.05 mm (0.026 ∼ 0.041 in.)

KX250 0.45 ∼ 0.85 mm (0.018 ∼ 0.033 in.)

Crankshaft Sensor Resistance 180 ∼ 280 Ω

Magneto Output Voltage in the text

Magneto Coil Resistance

in the text

Regulator/Rectifier (KX250):

Internal Resistance in the text

Out Put Voltage

14.7 ±0.5 V

Ignition System

Ignition Timing:

KX125

13° BTDC @9 710 r/min (rpm)

KX250 (Disconnect the throttle sensor lead) 14° BTDC @7 740 r/min (rpm)

Ignition Coil:

3 Needle Arcing Distance 7 mm (0.26 in.) or more

Primary Winding Resistance:

KX125-M1 ∼ M3 0.24 ±0.04 Ω (at 20°C)

KX125M6F ∼ 0.33 ±0.05 Ω (at 20°C)

KX250 0.53 ±0.08 Ω (at 20°C)

Secondary Winding Resistance:

KX125-M1 ∼ M3

8.3 ±1.2 kΩ (at 20°C)

KX125M6F ∼ 9.0 ±1.4 Ω (at 20°C)

KX250 12.6 ±1.9 kΩ (at 20°C)

Spark Plug:

Type:

KX125-M1 NGK BR9EIX

KX125-M2 ∼ M3 NGK R6918B-9

KX125M6F ∼ NGK BR9ECMVX

KX250 NGK BR8EIX

Gap 0.7 ∼ 0.8 mm (0.026 ∼ 0.031 in.)

C.D.I. Unit in the text

Noise Suppressor Resistance 3.75 ∼ 6.25 Ω

Throttle Sensor: (KX250)

Input Voltage around 5 V

Output Voltage:

(when the throttle valve completely closed). 0.4 ∼ 0.6 V

(when the throttle fully opened). 3.5 ∼ 3.7 V

Fuel Cut Valve: (KX250)

Resistance

49.7 ∼ 56.2 Ω

Protrusion:

When Battery is Disconnected 19.4 ∼ 19.6 mm (0.76 ∼ 0.77 in.)

When Battery is Connected 21.3 ∼ 21.7 mm (0.84 ∼ 0.85 in.)

ELECTRICAL SYSTEM 14-7

Special Tools

Spark Plug Wrench, Hex 21:

57001-110

Flywheel Puller, M 12 × 1.75:

57001-252

Hand Tester:

57001-1394

Peak Voltage Adapter:

57001-1415

Flywheel & Pulley Holder:

57001-1605

14-8 ELECTRICAL SYSTEM

Precautions

There are numbers of important precautions that are

musts when servicing electrical systems. Learn and ob-

serve all the rules below.

○

The electrical parts should never be struck sharply, as

with a hammer, or allowed to fall on a hard s urface. Such

a shock to the parts can damage them.

○

Troubles may involve one or in some cases all items.

Never replace a defective part without determining what

CAUSED the failure. If the failure was caused by some

other item or items, they too must be repaired or replaced,

or the new replacement will soon fail again.

○

Make sure all connectors in the circuit are clean and tight,

and examine leads for signs of burning, fraying, etc. Poor

leads and bad connections will affect electrical system

operation.

○

Measure coil and winding resistance when the part is cold

(at room temperature).

○

Electrical Connectors

[A] Female Connectors

[B] Male Connectors

Safety Instructions:

WARNING

The ignition system produces extremely high volt-

age. Do not touch the spark plug, ignition coil, or

high tension lead while the engine is running, or

you could receive a severe electrical shock.

ELECTRICAL SYSTEM 14-9

Electrical Wiring

Wiring Inspection

•

Visually inspect the wiring for signs of burning, fraying,

etc.

If any wiring is poor, replace the damaged wiring.

•

Pull each connector [A] apart and inspect it for corrosion,

dirt, and damage.

If the connector is corroded or dirty, clean it carefully. If it

is damaged, replace it.

•

Check the wiring for continuity.

○

Use the wiring diagram to find the ends of the lead which

is suspected of being a problem.

○

Connect an ohmmeter between the ends of the leads.

○

Set the meter to the x 1 Ω range, and lead the meter.

If the meter does not read 0 Ω the lead is defective. Re-

place the lead or the wiring harness if necessary.

14-10 ELECTRICAL SYSTEM

Ignition Timing

Ignition Timing Adjustme nt

•

Remove the magneto cover.

•

Check to see if the center mark of the three marks [A]

on the magneto stator is aligned with the mark [B] on the

crankcase.

If the marks are not aligned, loosen the magneto stator

screws [C] and turn the magneto stator [D].

•

Tighten the screws securely.

Torque - Stator Plate Mounting Screws: 4.4 N·m (0.45

kgf·m, 39 in·lb)

•

Install the magneto cover.

•

Tighten:

Torque - Magneto Cover Bolts:

4.9 N·m (0.5 kgf·m, 43 in·lb) (KX125/250-M1)

3.5 N·m (0.4 kgf·m, 35 in·lb) (KX125/250-M2 ∼)

The ignition timing can be adjusted for different power

band to suit to rider’s preference ability.

•

Remove the magneto cover.

•

Loosen the stator screws.

•

Adjust the timing by shifting the stator position within the

three lines [A].

ELECTRICAL SYSTEM 14-11

Ignition Timing

NOTE

○

For best engine performance, it is very important to ad-

just the ignition timing within the adjustable range just

explained.

Crankshaft Rotation [A]

Stator Movement [B]

Retard [C]

Advance [D]

•

Tighten the stator screws securely (see Igniting Timing

Adjustment).

•

Install the magneto cover (see Ignition Timing Adjust-

ment).

•

Tighten:

Torque - Magneto Cover Bolts:

4.9 N·m (0.5 kgf·m, 43 in·l b) (KX125/2 50-M1)

3.5 N·m (0.4 kgf·m, 35 in·lb) (KX125/250-M2 ∼)

•

Test ride the motorcycle and readjust the ignition timing if

necessary.

14-12 ELECTRICAL SYSTEM

Flywheel Magneto

Flywheel Magneto R emoval

•

Remove the magneto cover.

•

Hold the flywheel steady, w ith the flywheel holder [A], and

remove the flywheel bolt (KX125) or nut (KX250) [B].

Special Tool - Flywheel & Pulley Holder: 57001-1605

•

Remove the flywheel holder.

•

Screw the flywheel puller [A] into the flywheel by turning

it counterclockwise ( left-hand thread).

•

Remove the flywheel from the crankshaft by turning in the

puller center bolt and tapping the head of the bolt lightly

with a hammer, while holding the puller body steady.

There is a woodruff key in the crankshaft tapered portion.

Special Tool - Flywheel Puller, M12 × 1.75: 57001-252

CAUTION

Never strike the grab bar or the flywheel itself. Strik-

ing the bar can bend it. If the flywheel is strike, the

magnets may lose their magnetism.

•

Unscrew the mounting screws [A], and remove the s tator

plate [B] and the wiring grommet [C].

•

Remove the band.

KX125:

•

Remove the number plate.

•

Disconnect the magneto lead connector [A] from the C.D.I

unit.

ELECTRICAL SYSTEM 14-13

Flywheel Magneto

KX250:

•

Remove the left radiator shroud.

•

Disconnect the magneto lead connector [A] from the main

harness.

Flywheel Magneto Installation

•

Using a high-flash point solvent, clean off any oil or dirt

that may be on the crankshaft taper [A] or in the hole [B]

in the flywheel. Dry them with a clean cloth.

•

Fit the woodruff key [A] securely in the slot in the crank-

shaft before installing the stator plate.

•

Apply silicone sealant around the circumference of the

wiring grommet.

•

Set the stator wiring grommet [A] securely in the notch [B]

in the left crankshaft half, and route the wires according

to the Cable, Harness, Hose Routing section in the Ap-

pendix c hapter.

•

Install the stator plate and tighten it.

Torque - Stator Plate Mounting Screws: 4.4 N·m (0.45

kgf·m, 39 in·lb)

•

Holding the flywheel steady, with the flywheel holder, and

tighten the flywheel bolt (KX125) or nut (KX250).

Special Tool - Flywheel & Pulley Holder: 57001-1605

Torq ue - Fly wheel Bolt (KX125) : 22 N·m (2.2 kgf·m, 16 ft·lb)

Flywheel Nut (KX250): 78 N·m (8.0 kgf·m, 58 ft·lb)

14-14 ELECTRICAL SYSTEM

Flywheel Magneto

•

Measure the crankshaft sensor air gap [A] (Clearance be-

tween the flywheel and the crankshaft sensor [B] c ore.)

Crankshaft Sensor Air Gap

Standard:

KX125-M1 ∼ M6F

0.45 ∼ 0.85 mm (0.018 ∼ 0.033 in.)

KX125M7F ∼

0.65 ∼ 1.05 mm (0.026 ∼ 0.041 in.)

KX250

0.45 ∼ 0.85 mm (0.018 ∼ 0.033 in.)

If the gap is incorrect, adjust it (see this chapter).

•

Replace the gasket with a new one.

•

Connect the magneto lead connector to the C.D.I. unit

(KX125) or main harness (KX250).

Flywheel Magneto In spection

•

There are three types of magneto problems: short, open

(wire burned out), or loss in flywheel magnetism. A short

or open in one of the coil wires will result in either a low

output, or no output at all. A loss in flywheel magnetism,

which may be caused by dropping or hitting the flywheel

by leaving it near an electromagnetic field, or just by ag-

ing, will result in low output.

•

Check the magneto output voltage, do the following pro-

cedures.

○

Disconnect the magneto lead connector [A].

ELECTRICAL SYSTEM 14-15

Flywheel Magneto

○

Connect the auxiliary leads between the C.D.I unit [A]

(KX125) or main harness connector [A] (KX250) and the

magneto lead connector [B].

○

Connect the hand tester as shown in the table 1.

○

Start the engine.

○

Run it at the rpm given in the table 1.

○

Note the voltage readings (total 2 measurements).

Table 1 Magneto Output Voltage

(1) KX125

Connections

Reading

Tes te r

Range

Tes ter (+ ) to Te st er ( –) t o @4 000 rpm

250 V AC

White lead Red lead 80 V or more

(2) KX250

Connections Reading

Tes t er

Range

Tes ter (+ ) to Te s te r ( –) to @ 4 000 rpm

250V AC

White lead Red lead 59 V or more

50 V AC

Yellow/White

lead

Yellow lead 16 V or more

If the output voltage shows the value in the table, the mag-

neto operates properly.

If the output voltage shows a much higher than the value

in the table, the regulator/rectifier is damaged. A much

lower reading than that given in the table indicates that

the magneto is defective.

•

To check the stator coil resistance as follows.

○

Stop the engine.

○

Disconnect the auxiliary leads.

○

Connect the hand tester as shown in the table 2.

○

Note the readings (total 2 measurement).

(1) KX125

Connections

Tes t er

Range

Tes ter (+) to Te st e r ( –) to

Reading

x1Ω

White lead Red lead

10 ∼ 30 Ω

(2) KX250

Connections

Tes te r

Range

Tes t er ( +) t o Tes te r (– ) t o

Reading

White lead Red lead 10 ∼ 30 Ω

×1Ω

Yellow/White lead

Yellow lead

1 ∼ 4Ω

14-16 ELECTRICAL SYSTEM

Flywheel Magneto

If there is more resistance than shown in the table, or no

hand tester reading (infinity) the stator has an open lead

and must be replaced. Much less than this resistance

means the stator is shorted, and must be replaced.

•

Using the highest resistance range of the hand tester,

measure the resistance between each leads and chas-

sis ground.

Any hand tester reading less than infinity (∞) indicates a

short, necessitating stator replacement.

If the stator coils have normal resistance, but the voltage

check showed the magneto to be defective; then the rotor

magnets have probably weakened, and the rotor must be

replaced.

Special Tool - Hand Tester: 57001-1394

Regulator/Rectifier Removal (KX250)

•

Remove:

Left Radiator Shroud

Band [A]

•

Disconnect the regulator/rectifier lead connector [B].

•

Unscrew the mounting bolt, and remove the regulator/rec-

tifier [C].

Regulator/Rectifier Output Voltage Inspection

(KX250)

•

Warm up the engine to obtain actual magneto operating

conditions.

•

Stop the engine, and disconnect the regulator/rectifier

lead connector.

•

Using an auxiliary leads, connect the regulator/rectifier

connector [A] and main harness connector [B].

•

Connect the hand tester [C] as shown in the table.

•

Start the engine, and note the v oltage readings at vari-

ous engine speeds. The readings should show under the

specified voltage when the engine speed is low and, as

the engine speed rises, the readings should also rise.

ELECTRICAL SYSTEM 14-17

Flywheel Magneto

Regulator/Rectifier Output Voltage

Connections

Tester Range

Tes ter ( +) Tes ter (–) t o

Reading

25 V D C Red/White Blac k/Yellow

14.2 ∼ 15.2 V

•

Push off the stop switch to stop the engine, and discon-

nect the hand tester.

If the regulator/rectifier output voltage is kept between the

values given in the table, the charging system is consid-

ered to be working normally.

If the output voltage is much higher than the values spec-

ified in the table, the regulator/rectifier is defective or the

regulator/rectifier leads are loose or open.

If the output voltage does not rise as the engine speed

increases, then the regulator/rectifier is defective or the

magneto output is insufficient for the loads. Check the

gneto and regulator/rectifier to determine which part is

defective.

Regulator/Rectifier Inspec tion (KX250)

•

Remove the regulator/rectifier.

•

Set the hand t

ester x 100 Ω range, measure the internal

resistance in both directions between the terminals.

Special Tool - Hand Tester: 57001-1394

If the reading i

s not specified v alue, replace the regula-

tor/rectifier.

Internal Resistance Unit: Ω

Tester (+) Lead

Terminal

R/W

Y/W BK/Y

R/W

–

500 ∼ 5K 500 ∼ 5K 300 ∼ 3K

Y 500 ∼ 5K

–

500 ∼ 50 K 500 ∼ 5K

Y/W

500 ∼ 5K 500 ∼ 50K

–

500 ∼ 5K

(–)*

BK/Y

300 ∼ 3K 200 ∼ 20K 200 ∼ 20K

–

(–)*: Tester (–) Lead Connection

CAUTION

Use only Hand Tester 57001-1394 for this test. An

ohmmeter other than the Hand Tester may show

different readings. If a megger or a meter with a

large-capacity battery is used, the r egu lator will be

damaged.

14-18 ELECTRICAL SYSTEM

Ignition System

Safety Instructions

WARNING

The ignition system produces extremely high volt-

age. Do not touch the spark plug, ignition coil, or

high tension lead while the engine is running, or

you could receive a severe electrical shock.

Ignition Coil Removal

•

Remove:

Seat

Radiator Shrouds

Fuel Tank

•

Disconnect the ignition coil primary lead [A].

•

Pull the plug cap [B] off the spark plug.

•

Unscrew the mounting bolts [C], and remove the ignition

coil [D].

Ignition Coil Inspection

Measuring arcing distance

The most accurate test for determining the condition of

the ignition coil is made by measuring arcing distance using

the coil tester for the 3-needle method.

•

Remove the ignition coil.

•

Connect the ignition coil (with the spark plug cap left in-

stalled on the high tension lead) [A] to the tester [B], and

measure the arcing distance.

WARNING

To avoid extremely high voltage shocks, do not

touch the coil or lead.

If the distance reading is less than the specified value, the

ignition coil or spark plug cap is defective.

3 N eedle Arcing Distance

Standard: 7 mm (0.26 in.) or more

•

To determine which part is defective, measure the arcing

distance again with the spark plug cap removed from the

ignition coil lead.

If the arcing distance i s subnormal as before, the trouble

is with the ignition coil itself. If the arcing distance is now

normal, the trouble is with the spark plug cap.

ELECTRICAL SYSTEM 14-19

Ignition System

Measuring Coil Resistance

If the arcing tester is not available, the coil can be

checked for a broken or badly shorted winding with an

ohmmeter. However, an ohmmeter cannot detect layer

shorts and shorts resulting from insulation breakdown

under high voltage.

•

Remove the i gnition coil.

•

Measure the primary winding resistance [A].

○

Connect an ohmmeter between the coil terminals.

○

Set the meter to the x 1 Ω range, and read the meter.

•

Measure the secondary winding resistance [B].

○

Pull the spark plug cap off the lead.

○

Connect an ohmmeter between the high tension lead and

the ground lead terminal.

○

Set the meter to the x 1 kΩ range, and read the meter.

If the meter does not read as specified, replace the coil.

If the meter reads as specified, the ignition coil windings

are probably good. However, if the ignition system still

does not perform as it should after all other components

have been checked, test replace the coil with one known

to be good.

Ignition Coil Winding Resistance

Primary windings:

KX125-M1 ∼ M3

0.24 ±0.04 Ω (at 20°C)

KX125M6F ∼

0.33 ±0.05 Ω (at 20°C)

KX250

0.53 ±0.08 Ω (at 20°C)

Secondary windings:

KX125-M1 ∼ M3

8.3±1.2kΩ (at 20°C)

KX125M6F ∼

9.0±1.4kΩ (at 20°C)

KX250

12.6 ±1.9 kΩ (at 20°C)

•

Check the high tension lead for visible damage.

If the s park high tension is damaged, replace the coil.

Spark Plug Cleaning and Inspection

•

Refer to the Spark Plug Cleaning and Inspection in the

Periodic Maintenance chapter.

Spark Plug G ap Inspection

•

Refer to the Spark Plug Gap Inspection in the Periodic

Maintenance chapter.

C.D.I Unit Removal

•

Remove the number plate.

•

Disconnect the magneto lead connector [A] (KX125) or

main harness connector (KX250).

•

Unscrew the mounting bolt [B] and remove the C.D.I Unit

[C].

14-20 ELECTRICAL SYSTEM

Ignition System

C.D.I Unit Inspection

CAUTION

When inspecting the C.D.I. unit observe the follow-

ing to avoid damage to the C.D.I. unit.

Do not disconnect the C.D.I. unit while the engine is

running.

This may damage the C.D.I. unit.

Ignition Coil Primary Peak Voltage Check

•

Disconnect the spark plug cap from mounting the spark

plug.

•

Connect the good spark plug [A] to the spark plug cap,

then touch the engine with the spark plug.

NOTE

○

Measure the voltage with each lead connected cor-

rectly. The correct value may not be obtained if

disconnected.

○

Maintain the correct value of compression pressure for

the cylinder. (Be sure to measure the voltage with the

spark plug install to the cylinder head.)

○

The correct value may not be obtained if disconnected.

•

Connect the peak voltage adapter [B] between the termi-

nal of primary lead (orange) and ground connection of the

unit with the lead of the ignition coil [C] connected.

Special Tool:

Peak Voltage Adapter: 57001-1415

Type: KEK-54-9-B

Connection: Tester Positive → GroundLead[D]

Tester Negativ e →Orange Lead [E]

C.D.I Unit [F]

•

Shift the gear to the neutral position, then free the engine

stop switch.

•

Crank the engine by kicking the pedal several times to

measure the peak voltage of the primary ignition coil.

Primary Voltage:

KX125-M1 ∼ M3: 200 V or above

KX125M6F ∼ 160 V or above

KX250 150 V or above

WARNING

Do not touch the metal portion of the probe in case

of measuring the voltage, or you may receive a se-

rious electric shock.

If the voltage is less than the specified value, see the next

page.

ELECTRICAL SYSTEM 14-21

Ignition System

14-22 ELECTRICAL SYSTEM

Ignition System

Crankshaft Sensor Peak Voltage Check

•

To check the peak voltage, do the following procedures.

○

Disconnect the connector of the magneto lead connec-

tor from the C.D.I. unit (KX125), or the main harness

(KX250).

NOTE

○

Measure the voltage with each lead connected cor-

rectly. The correct value may not be obtained if

disconnected.

○

Maintain the correct value of compression pressure for

the cylinder (Be sure to measure the voltage with the

spark plug installed to the cylinder head).

○

The correct value may not be obtained if disconnected.

○

Connect the peak voltage adapter [A] of the tester to the

terminals of the magneto lead connector [B].

Special Tool:

Peak Voltage Adapter: 57001-1415

Type: KEK-54-9-B

Connection: Adapter Positive → Green/White Lead

[C]

Adapter N e gative → White/Yellow

Lead [D]

○

Crank the engine by kicking the pedal several times to

measure the peak voltage of the crankshaft sensor.

Peak Voltage :

KX125-M1 ∼ M3: 2.4 V or above

KX125M6F ∼ 1.6 V or above

KX250 1.6 V or above

WARNING

Do not touch the metal portion of the probe in case

of measuring the voltage, or you may receive a se-

rious electric shock.

If the voltage is less than the specified, check the crank-

shaft sensor.

ELECTRICAL SYSTEM 14-23

Ignition System

Exciter Coil Peak Voltage Check

•

Disconnect the connector of the magneto lead connec-

tor from the C.D.I. unit (KX125), or the main harness

(KX250).

•

To check the peak voltage, do the following procedures.

NOTE

○

Measure the voltage with each lead connected cor-

rectly. The correct value may not be obtained if

disconnected.

○

Maintain the correct value of compression pressure for

the cylinder (Be sure to measure the voltage with the

spark plug installed to the cylinder head).

○

The correct value may not be obtained if disconnected.

○

Connect the peak voltage adapter [A] of the tester to the

terminals of the magneto lead connector [B].

Special:

Peak Voltage Adapter: 57001-1415

Type: KEK-54-9-B

Connection: Adapter Positive → White Lead [C]

Adapter Negative → Red Lead [D]

○

Crank the engine by kicking the pedal several times to

measure the peak voltage of the exciter coil.

Peak Voltage :

KX125: 32 V or above

KX250: 16 V or above

If the voltage is less than the specified, check the exciter

coil.

Fuel Cut Valve Operation Check: (KX250)

•

Disconnect the carburetor lead connector [A].

•

Set the tester to the DC25V range, and connect it to the

carburetor lead of the main harness side.

Connections:

Tester Po si ti ve → Red/White Lead [B]

Tester Negative → BrownLead[C]

•

Start the engine.

•

Run it at the rpm given below.

Fuel Cut Valve Operate Revolutions

Standard:

8100rpm

•

Read the tester, running the engine at the specified revo-

lution.

Fuel Cut Valve Operation Voltage:

When engine is specified revolutions or above: DC 12 V

When en gine is less than specified revolutions: 0 V

If the tester does not read as specified, check the mag-

neto.

If the m agneto has normal functions, replace the C.D.I.

Unit.

14-24 ELECTRICAL SYSTEM

Ignition System

Throttle Sensor Output/Input Voltage Check: (KX250)

NOTE

○

If the variable rheostat is available, refer to throttle sen-

sor inspection.

•

Remove the carburetor lead connector.

•

Connect the auxiliary leads [A] between carburetor lead

connector [B] and main harness connector [C].

•

Set the tester to the DC 10V range, and connect it to the

auxiliary leads.

Hand Tester (+) → Red/Green Lead

Hand Tester (–) → Black/Green Lead

•

Start the engine.

•

Check the sensor input voltage with the engine running.

Throttle Sensor Input Voltage

Standard:

4 V or above

If it is not within the s pecified voltage range, check the

magneto output voltage. If it has normal functions, re-

place the C.D.I. Unit.

•

To check the output voltage, do the following procedures.

○

Using the auxiliary leads [A], connect the hand tester [B]

as follows.

Hand Tester (+) → White/Black Lead

Hand Tester (-) → Black/Gree n Lea d

○

Remove the spark plug.

○

Crank the engine by kicking the pedal several times to

measure the throttle sensor output voltage with the throt-

tle valve completely closed.

Throttle Sensor Output Voltage

Standard:

0.4 ∼ 0.6 V (when throttle valve is

completel y closed.)

If it is not within the specified voltage range, adjust the

throttle sensor position (see Throttle Sensor Position Ad-

justment).

If it is within specified voltage, go to next test.

○

Crank the engine by kicking the pedal several times to

measure the throttle sensor output voltage with the throt-

tle fully opened.

Throttle Sensor Output Voltage

(when the throttle fully opened)

Standard:

3.5 ∼ 3.7 V

If it is not within the specified voltage, replace the throttle

sensor.

Engine Stop Switch Electric Curren t Check:

•

Disconnect the engine stop switch lead.

•

Start the engine.

•

Ground the stop switch lead of the main harness side

while the engine is running.

If does not stop the engine, replace the C.D.I Unit.

ELECTRICAL SYSTEM 14-25

Ignition System

Crankshaft Sensor Inspection

•

Remove:

Magneto Lead Connector (see Flywheel Magneto In-

spection).

•

Set the hand tester [A] to the × 100Ω range and connect it

to the Green/White [B] and White/Yellow [C] Leads in the

connector.

Special Tool - Hand Tester: 57001-1394

If there is more resistance than the specified value, the

coil has an open lead and must be replaced. Much less

than this resistance means the coil is shorted, and must

be replaced.

Crankshaft Sensor

Resistance:

180 ∼ 280 Ω

•

Using the highest resistance range of the tester, measure

the resistance between the c rankshaft sensor leads and

chassis ground.

Any tester reading less than infinity (∞) i ndicates a short,

necessities replacement of the crankshaft sensor assem-

bly.

Crankshaft Sensor Air Gap Adjustment

•

Loosen the crankshaft sensor screws [A].

•

Insert the thickness gauge [B] between the crankshaft

sensor core and the timing plat.

Thickness Gauge [B]

Standard:

KX125-M1 ∼ KX125M6F

0.65 mm (0.026 in.)

KX125M7F ∼

0.85 mm (0.033 in.)

KX250-M1 ∼ M2

0.65 mm (0.026 in.)

•

While pressing the crankshaft sensor toward the magneto

flywheel, tighten the coil screws and remove the thickness

gauge.

•

Check the air gap (see Flywheel Magneto Installation).

If the air gap is not within the specified range, readjust the

gap.

14-26 ELECTRICAL SYSTEM

Throttle Sensor

Throttle Sensor Inspection (KX250)

NOTE

○

If the variable rheostat is not available, refer to throttle

sensor output/input voltage check in the C.D.I Unit in-

spection.

○

When inspecting the throttle sensor the throttle valve of

the carburetor shall be completely closed and remain

the throttle cable connected.

•

Remove the carburetor (see Fuel System chapter).

•

Connect the carburetor lead connector [A] with the battery

[B], variable rheostat [C] and hand testers [D] as shown.

Variable Rheostat (+) → R/G Lead Terminal [E]

Hand Tester (+) → W/BK Lead terminal [F]

Hand Tester (–) → BK/G Lead terminal [G]

•

Check the sensor input voltage.

Throttle Sensor Input Voltage

Standard: a round 5 V

•

Check the sensor output voltage with the throttle valve is

completely closed.

Throttle Sensor Output Voltage

Standard:

0.4 ∼ 0.6 V (when the throttle valve

comp letely closed.)

If it is not within the specified voltage, adjust the throt-

tle sensor position (see Throttle Sensor Position Adjust-

ment).

If it is within specified voltage, go to next test.

•

Check the sensor output voltage with the throttle fully

opened.

Throttle sensor Output Voltage

Standard: 3.5 ∼ 3.7 V (When throttle fully opened.)

If it is not within the specified voltage, replace the sensor.

Throttle Sensor Position Adjustment (KX250)

•

Remove the carburetor.

•

Check the throttle v alve is completely closed.

•

Loosen the throttle sensor mounting bolt [A].

•

Connect the carburetor lead connector with the battery,

variable rheostat and handtesters in the same manner as

specified in the throttle sensor Inspection.

•

Adjust the position of the sensor until the output voltage

is within the specified voltage range.

Throttle Sensor Output Voltage

Standard:

0.4 ∼ 0.6 V (when throttle valve is

completel y closed.)

•

If it is not within the specified voltage range, replace the

sensor.

ELECTRICAL SYSTEM 14-27

Fuel Cut Valve

Fuel Cut Valve Removal (KX250)

WARNING

Gasoline is extremely flammable and can be ex-

plosive under certain conditions. Turn the ignition

switch OFF. Do not smoke. Make sure the area is

well-ventilated and free from any source of flame

or sparks; this includes any appliance with a pilot

light.

•

Disconnect the carburetor lead connector.

•

Remove the carburetor.

•

Drain the fuel from the float bowl removing the drain plug.

After draining, install the drain plug securely.

•

Loosen the fuel cut valve [A] and remove it.

Fuel Cut Valve Installation (KX250)

•

Installation is reverse of removal.

Fuel Cut Valve Inspection (KX250)

•

Remove the fuel cut valve [A].

•

Connect and disconnect one 12 V battery [B] to the car-

buretor lead connector as shown. The valve rod moves.

If the protrusion exceeds the standard (too long or too

short), the valve is defective and must be replaced.

Testing Fuel Cut Valve

Standard Protrusion:

When battery is disconnected ← 19.4 ∼ 19.6 mm (0.76

∼ 0.77 in.)

When battery is connected ← 21.3 ∼ 21.7 mm (0.84 ∼

0.85 in.)

APPENDIX 15-1

Appendix

Table of Contents

Troubleshooting Guide ........................................................................................................... 15-2

Cable, Wire and Hose Routing ............................................................................................... 15-6

15-2 APPENDIX

Troubleshooting Guide

NOTE

○

This is not an exhaustive list, giving every

possible cause for each problem listed. It

is meant simply as a rough guide to assist

the troubleshooting for some of the more

common difficulties.

Engine Doesn’t Start, Starting

Difficulty:

Engine won’t turn over:

Cylinder, piston seizure

Crankshaft seizure

Connecting rod small end seizure

Connecting rod big end s eizure

Transmission gear or bearing seizure

Kick shaft return spring broken

Kick ratchet gear not engaging

No fuel flow:

No fuel in tank

Fuel tap turned off

Tank cap air vent obstructed

Fuel tap clogged

Fuel line clogged

Float valve clogged

Fuel cut valve left close

Engine flooded:

Float level too high

Float valve worn or stuck open

Starting technique faulty

(when flooded, kick with the throttle fully

open to

allow more air to reach the engine.)

No spark; spark weak:

Spark plug dirty, broken, or maladjusted

Spark plug cap or high tension wiring trou-

ble

Spark plug cap not in good contact

Spark plug incorrect

C.D.I Unit trouble

Ignition coil trouble

Ignition coil resistor open

Flywheel magneto damaged

Wiring shorted or open

Fuel/air mixture incorrect:

Idle adjusting screw maladjusted

Slow jet or air passage clogged

Air cleaner clogged, poorly sealed, or miss-

ing

Starter jet clogged

Compression Low:

Spark plug loose

Cylinder head not sufficiently tightened

down

Cylinder, piston worn

Piston ring bad (worn, weak, broken, or

sticking)

Piston ring/groove clearance excessive

Cylinder head gasket damaged

Cylinder head warped

Cylinder base gasket damaged

Read valve damaged

Cylinder nut loose

Poor Running at Low Speed:

Spark weak:

Spark plug dirty, broken, or maladjusted

Spark plug cap or high tension wiring trou-

ble

Spark plug cap shorted or not in good con-

tact

Spark plug incorrect

C.D.I Unit trouble

Ignition coil trouble

Flywheel magneto damaged

Ignition coil lead or C.D.I Unit lead not in

good contact

Fuel/air mixture incorrect:

Idle adjusting screw maladjusted

Slow jet or air passage clogged

Air c leaner clogged, poorly sealed, or miss-

ing

Starter plunger stuck open

Float level too high or too low

Fuel tank air vent obstructed

Fuel cut valve won’t fully open

Carburetor holder loose

Air cleaner duct loose

Compression Low:

Spark plug loose

Cylinder head not sufficiently tightened

down

Cylinder, piston w orn

Piston ring bad (worn, weak, broken, or

sticking)

Piston ring/groove clearance excessive

Cylinder head gasket damaged

Cylinder head warped

Cylinder base gasket damaged

Reed valve damaged

Cylinder nut loose

Kips ports stuck open:

KIPS exhaust valve stuck open (valve

seizure, or carbon accumulation)

KIPS exhaust valves assembled incorrectly

Exhaust advancer spring damaged

Exhaust valve operating rod seizure

Rod (for KIPS) seized in cylinder

Other:

C.D.I Unit trouble

Transmission oil viscosity too high

Brake dragging

APPENDIX 15-3

Troubleshooting Guide

Poor Running or No Power at High

Speed:

Firing incorrect:

Spark plug dirty, damaged, or maladjusted

Spark plug cap or high tension wiring dam-

aged

Spark plug cap shorted or not in good con-

tact

Spark plug incorrect

C.D.I Unit trouble

Ignition coil trouble

Flywheel magneto damaged

Ignition coil lead or C.D.I Unit lead not in

good contact

Fuel/air mixture incorrect:

Main jet clogged or wrong size

Jet needle or needle j et worn

Jet needle clip in wrong position

Float level too high or too low

Fuel cut valve won’t fully open

Air jet or air passage clogged

Air cleaner clogged, poorly sealed, or miss-

ing

Starter p lunger stuck open

Fuel to carburetor insufficient

Water or foreign matter in fuel

Fuel tank air vent obstructed

Carburetor holder loose

Air cleaner duct loose

Fuel tap clogged

Fuel line clogged

Compression low:

Spark plug loose

Cylinder head not sufficiently tightened

down

Cylinder, piston worn

Piston ring bad (worn, weak, broken, or

sticking)

Piston ring/and clearance excessive

Cylinder head gasket damaged

Cylinder head warped

Cylinder base gasket damaged

Reed valve damaged

Cylinder nut loose

Engine rpm will not rise properly:

Starter p lunger stuck open

Float level too high or too low

Main jet clogged

Throttle valve does not fully open

Air cleaner clogged

Muffler clogged

Water or foreign matter in fuel

Cylinder exhaust port clogged

Brake dragging

Clutch slipping

Overheating

Transmission oil level too high

Transmission oil viscosity too high

Crankshaft bearing worn or damaged

KIPS ports stuck closed:

KIPS ports stuck closed

KIPS exhaust valves stuck closed (valve

seizure, or carbon accumulation)

KIPS exhaust valves assembled incorrectly

KIPS ports clogged (carbon accumulation)

Exhaust valve operating rod seizure

Rod (for KIPS) seized in cylinder

Knocking:

Carbon built up in combustion chamber

Fuel poor quality or i ncorrect

Spark plug incorrect

C.D.I Unit trouble

Overheating:

Firing incorrect:

Spark plug dirty, broken, or maladjusted

Spark plug incorrect

C.D.I Unit trouble

Fuel/air mixture incorrect:

Main jet clogged or wrong size

Fuel level in c arburetor float bowl too low

Fuel cut valve won’t fully open

Carburetor holder loose

Air cleaner poorly sealed, or missing

Air cleaner duct poorly sealed

Air cleaner clogged

Compression high:

Carbon built up in combustion chamber

Engine load faulty:

Brake dragging

Clutch slipping

Transmission oil level too high

Transmission oil viscosity too high

Lubrication inadequate:

Transmission oil level too low

Transmission oil poor quality or incorrect

Coolant incorrect:

Coolant level too low

Coolant deteriorated

Cooling system component incorrect:

Radiator clogged

Radiator cap trouble

Water pump not rotating

Clutch Operation Faulty:

Clutch slipping:

No clutch lever play

Clutch cable m aladjusted

Clutch inner cable catching

Friction plate worn or warped

Steel plate worn or warped

Clutch spring broken or weak

Clutch release mechanism trouble

Clutch hub or housing unevenly worn

15-4 APPENDIX

Troubleshooting Guide

Clutch not disengaging properly:

Clutch lever play excessive

Clutch plate warped or too rough

Clutch spring tension uneven

Transmission oil deteriorated

Transmission v iscosity too high

Transmission oil level too high

Clutch housing frozen on drive shaft

Clutch release mechanism trouble

Gear Shifting Faulty:

Doesn’t into gear; shift pedal doesn’t

return:

Clutch not disengaging

Shift fork bent or seized

Gear stuck on the shaft

Gear positioning lever binding

Shift return spring weak or broken

Shift return spring pin loose

Shift mechanism arm spring broken

Shift mechanism arm broken

Shift drum broken

Jumps out of gear:

Shift fork worn

Gear groove worn

Gear dogs and/or dog holes worn

Shift drum groove worn

Gear positioning lever spring weak or bro-

ken

Shift fork guide pin worn

Drive shaft, output shaft, and/or gear

splines worn

Overshifts:

Gear positioning lever spring weak or bro-

ken

Shift mechanism arm spring broken

Abnormal Engine Noise:

Knocking:

C.D.I Unit trouble

Carbon built up in combustion chamber

Fuel poor quality or incorrect

Spark plug incorrect

Overheating

Piston slap:

Cylinder/piston clearance excessive

Cylinder, piston worn

Connecting rod bent

Piston pin, piston pin hole worn

Other noise:

Connecting rod small end clearance exces-

sive

Connecting rod big end clearance exces-

sive

Piston ring worn, broken or stuck

Piston seizure or damaged

Cylinder head gasket leaking

Exhaust pipe leaking at cylinder head con-

nection

Crankshaft runout excessive

Engine mounts loose

Crankshaft bearing worn

Primary gear worn or chipped

Abnormal Drive Train Noise

Clutch noise:

Clutch housing/friction plate clearance ex-

cessive

Clutch housing gear/primary gear backlash

excessive

Metal chip jammed in clutch housing gear

teeth

Transmission noise:

Crankcase bearing worn or damaged

Transmission gear worn or chipped

Metal chip jammed in gear teeth

Transmission oil insufficient or too thin

Kick ratchet gear not properly disengaging

from kick gear

Output shaft idle gear worn or chipped

Drive chain noise:

Drive chain adjusted improperly

Chain worn

Rear and/or engine sprocket(s) worn

Chain lubrication insufficient

Rear wheel misaligned

Abnormal Frame Noise:

Front fork noise:

Oil insufficient or too thin

Spring weak or broken

Front fork air pressure high

Rear shock absorber noise:

Shock absorber damaged

Disc brake noise:

Pad installed incorrectly

Pad surface glazed

Disc warped

Caliper trouble

Cylinder damaged

Other noise

Bracket, nut, bolt, etc. not p roperly

mounted or tightened

Exhaust Smoke:

Excessive white smoke:

Throttle cable maladjusted

Brownish smoke:

Air cleaner clogged

Main jet too large of fallen out

Starter plunger stuck open

Float level too high

APPENDIX 15-5

Troubleshooting Guide

Handling and/or Stability

Unsatisfactory:

Handlebar hard to turn:

Control Cable routing incorrect

Wiring routing incorrect

Steering stem locknut too tight

Bearing ball damaged

Bearing race dented or worn

Steering s tem bearing lubrication inade-

quate

Steering stem bent

Tire air pressure too low

Handlebar shakes or excessively vibrates:

Tire worn

Swingarm sleeve or needle bearing dam-

aged

Rim warped, or not balanced

Front, rear axle runout excessive

Wheel bearing worn

Handlebar clamp loose

Steering stem head nut loose

Handlebar pulls to one side:

Frame bent

Wheel misalignment

Swingarm bent or twisted

Swingarm pivot shaft runout excessive

Steering maladjusted

Steering stem bent

Front fork leg bent

Right/left front fork oil level uneven

Shock absorption unsatisfactory:

(Too hard)

Front fork oil excessive

Front fork oil viscosity too high

Front fork leg bent

Front fork air pressure high

Tire air pressure too high

Rear shock absorber maladjusted

(Too soft)

Front fork oil insufficient and/or leaking

Front fork oil viscosity too low

Front fork, rear shock absorber spring weak

Rear shock absorber gas leaking

Rear shock absorber maladjusted

Brake Doesn’t Hold:

Disc brake:

Air in the brake line

Pad or disc worn

Brake fluid leak

Disc warped

Contaminated pads

Brake fluid deteriorated

Primary or secondary cup damaged

Master cylinder scratched inside

Brake maladjustment (lever or pedal play

excessive)

15-6 APPENDIX

Cable, Wire and Hose Routing

KX125:

APPENDIX 15-7

Cable, Wire and Hose Routing

1. Throttle Cable

2. Clutch Cable

3. Engine Stop Switch Lead

4. Band

5. Radiator Overflow Tube

6. Right Screen

7. Run the overflow tube backward of the down tube.

8. Run the overflow tube outside of the engine mount bracket.

9. Run the overflow tube forward of the radiator connection hose.

10. Left Screen

11. Frame

12. C.D.I. Unit

13. Run the throttle cable left side of the stop switch lead.

14. Clamp the magneto lead (harness) and stop switch lead connector. Do not clamp the throttle

cable.

15. Run the magneto lead (Harness) thought the frame and radiator.

16. Magneto Lead (Harness)

17. Band (Clamp the magneto lead and air vent tube)

18. Magneto

19. Ignition Coil

20. Ignition Coil Primary Winding Lead

21. Tighten together with ignition coil ground lead and magneto lead (harness) ground as figure.

22. Ignition Coil Ground Lead

23. Air Vent Hose

24. Clamp the clutch cable.

25. To the C.D.I. Unit

26. Clamps (Install the magneto lead from this side)

27. To the Ignition coil

28. To the Magneto

29. Mating section on the clamp at outside. (KX125-M2 ∼)

30. Run the clutch cable above the number plate mounting bracket. (KX125M6F ∼)

A: KX125-M3 ∼ Model

B: KX125-M1 ∼ M3 Model

C: KX125M6F ∼ Model

15-8 APPENDIX

Cable, Wire and Hose Routing

KX250:

APPENDIX 15-9

Cable, Wire and Hose Routing

1. Throttle Cable

2. Clutch Cable

3. Engine Stop Switch Lead

4. Band

5. Radiator Overflow Tube

6. Right Screen

7. Run the overflow tube backward of the down tube

8. Run the overflow tube outside of the engine mount bracket

9. Run the overflow tube forward of the radiator connection pipe.

10. Left Screen

11. Frame

12. C.D.I. Unit

13. Run the throttle cable leftside of main harness.

14. Clamp the main harness and stop switch lead connector.

15. Regulator/Rectifier

16. Do not clamp the throttle cable.

17. Bands

18. Main Harness

19. Magneto Lead Connector

20. Ignition Coil

21. Ignition Coil Primary Winding Lead

22. Ignition Coil Ground Lead

23. Tighten together with the ignition coil lead ground and magneto lead (harness) ground.

24. Carburetor Lead Connector

25. Carburetor

26. Magneto

27. Clamp the clutch cable

28. Clamp the magneto lead

29. Install the spark plug cap so that the spark plug lead cable and spark plug cap do not touch the

cooling hose.

30. Run the clutch cable through the clamps.

31. Mating section on the clamp at outside. (KX250-M2 ∼)

15-10 APPENDIX

Cable, Wire and Hose Routing

KX125:

APPENDIX 15-11

Cable, Wire and Hose Routing

1. Clamps

2. Left Radiator

3. Right Radiator

4. To the steering stem hole.

5. Air Vent Hose

6. To the fuel tank cap

7. Radiator Overflow Tube

8. Run the radiator over flow tube outside of the engine mount bracket

9. Carburetor

10. Clamp

11. Run the air vent hoses and overflow tube through the clamp.

12. Air Vent Hoses

13. Over Flow Tube

14. Cooling Hose

15. Install the fuel hose between the vent hoses.

16. Run the radiator over flow tube between frame and right radiator.

17. Pay attention to inflection of the radiator over flow tube.

18. Do not face the pinch head of the clamp to the air cleaner duct side.

19. Air Cleaner Duct Side

A: KX125-M1 ∼ M3 Model

B: KX125M6F ∼ Model

15-12 APPENDIX

Cable, Wire and Hose Routing

KX125M6F ∼:

1. Run the spark plug lead inside of the radiator bracket.

2. Tighten together with ignition coil ground lead and magneto lead (harness) ground as figure.

3. Ignition Coil

4. Ignition Coil Ground Lead

5. Magneto Lead

6. Radiator Bracket

APPENDIX 15-13

Cable, Wire and Hose Routing

KX250:

1. Clamps

2. Left Radiator

3. Right Radiator

4. To the steering stem hole.

5. Air Vent Hose

6. To the fuel tank cap

7. Band

8. Carburetor Lead Connector

9. Run the radiator overflow tube outside of

the engine mount bracket.

10. Carburetor

11. Clamp the air vent hoses with clamps

which are installed together with engine

sprocket cover and run them along with

the engine sprocket cover.

12. Clamps

13. Air Vent Hoses

14. Run the radiator over flow tube between

frame and right radiator.

15. Pay attention to inflaction of the radiator

over flow tube.

15-14 APPENDIX

Cable, Wire and Hose Routing

KX125/250-M1 Model

APPENDIX 15-15

Cable, Wire and Hose Routing

1. Front Brake Reservoir

2. Banjo Bolts

3. Clamp

4. Clamp Brackets

5. Hose Guard

6. Front Brake Disc

7. Front Fork Guard

8. Bleed Valves

9. Front Brake Caliper

10. Rear Brake Caliper

11. Caliper Guard

12. Clamps

13. Rear Brake Reservoir

14. Rear Brake Master Cylinder

15. Bend the cotter pin end by along the joint pin.

16. Rear Brake Disc

17. Disk Guard

15-16 APPENDIX

Cable, Wire and Hose Routing

KX125/250-M2 Model ∼

APPENDIX 15-17

Cable, Wire and Hose Routing

1. Front Brake Reservoir

2. Banjo Bolts

3. Clamp

4. Clamp Brackets

5. Front Brake Disc

6. Front Fork Guard

7. Bleed Valves

8. Front Brake Caliper

9. Rear Brake Caliper

10. Caliper Guard

11. Clamps

12. Rear Brake Reservoir

13. Rear Brake Master Cylinder

14. Bend the cotter pin end by along the joint pin.

15. Rear Brake Disc

16. Disk Guard

MODEL APPLICATION

Year Model Beginning Frame No.

2003 KX125-M1

JKAKXRMC□3A000001 or

JKAKX125MMA000001

2003 KX250-M1

JKAKXMMC□3A000001 or

JKAKX250MMA000001

2004 KX125-M2

JKAKXRMC□4A010001 or

JKAKX125MMA010001

2004 KX250-M2

JKAKXMMC□4A010001 or

JKAKX250MMA010001

2005 KX125-M3

JKAKXRMC□5A016001 or

JKAKX125MMA016001

2006 KX125M6F

JKAKXRMC□6A021001 or

JKAKX125MMA021001

2007 KX125M7F

JKAKXRMC□7A025001 or

JKAKX125MMA025001

□:This digit in the frame number changes from one machine to another.

Part No.99924-1298-06

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