Manual de Taller BAJAJ DISCOVER 125 UG MANUAL TALLER 2018

Training Notes

The Training Notes are

a

compr

ehensive

training guide

on

service

and

maintenance operations

and

pr

ocedu r

es

to be

followed

by

service

personnel

at

authorised service centres

and

dealerships whilst attending

to the

Bajaj Discover125-UG.

The Training

Note

covers standard workshop procedures

simplified for easy learning and

understanding for service

technicians

worldwide.

NOTICE

All information contained in this Training Note is based on

the latest product information at the time of publication.

Bajaj Auto Limited accepts no liability for any inaccuracies

or omissions in this publication, although every possible

care has been taken to make it as complete and accurate

as possible. All procedures and specifications subject to

change without prior notice. The right is reserved to make

such changes at any time without prior notice.

Copyright

All Intellectual Property Rights, including but not limited

to Copyright, applying to this drawing and the information

contained therein vest solely and exclusively with Bajaj

Auto Limited. No part of this drawing may be copied or

reproduced, either in part or in full by any means, whether

mechanical or electronic, without prior written permission

of the authorized signatory of Bajaj Auto Limited. Bajaj

reserves all rights to deal with violations of this clause in

accordance with applicable laws.

©

Bajaj Auto Limited, 11

th

SEPT 2012.

DOC. NO.: 71112879,

REV. 00, March 2018

CIN L65993PN2007PLC130076

Contents

CHAPTER

1

I Read ..... I Learn

Identification

Salient Features

Technical Specification

Pre-Delivery Inspection Check List

Periodic Maintenance & Lubrication Chart

01

02

03

06

08

10

CHAPTER

2

Fuel System 13

14

15

16

18

19

CHAPTER

3

Engine & Transmission

21

22

25

27

38

40

42

44

CHAPTER

4

Vehicle (Frame)

Special Tools

Service Limits

Tightening Torques

Dos & Don’ts

46

47

49

50

51

CHAPTER

5

Electricals

54

55

61

67

68

53

Carburettor Specifications

Overview of Fuel System

Secondary Air Induction (SAI) System

Evaporative Emission System

Tune-up for Optimum Mileage

Special Tools

Engine Removal from Frame

Engine Dismantling & Assembling

Service Limits

Tightening Torque

Engine Lubrication Flow of Oil

Dos & Don’ts

Battery Specifications

Electrical Checking Procedure

Important SOP

Dos & Don’ts

Electrical Wiring Diagrams

I Read ..... I Learn

CHAPTER 1

Identification

Salient Features

Technical Specifications

Pre-Delivery Inspection Check List

Periodic Maintenance & Lubrication Chart

1

Bajaj Discover 125 UG Training Notes

Key Learning Points

Understanding the Complete Anatomy of

the Vehicle

Technical Specifications and Performance

Parameters

Briefing and Educating the Customer on

Appropriate Riding and Usage Discipline,

and Routine Maintenance

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Speedometer Details

1. Speedometer:

Vehicle speed will be displayed in speedometer in Km / Hr.

2. Odometer :

The Odometer shows the total distance that the vehicle has covered.

Odometer can not be reset to ‘Zero’.

3. Turn Signal Indicator (LH & RH) :

When Turn signal switch is turned to left or Right, Turn pilot Indicator -

LH or RH will flash.

4. Neutral Indicator:

When the transmission is in Neutral, Neutral indicator will glow.

5. Fuel Level Indicator:

It shows fuel level in fuel tank.

6. Low Fuel Indicator :

It blinks incase of low fuel level (1 bar or less).

7. Hi Beam Indicator:

When Headlight is ‘ON’ & Hi beam is selected, Hi beam indicator will

glow.

8. Low Battery Indicator :

It indicates battery needs charging.

9. Bajaj Logo:

Bajaj logo flying ‘B’ continuously glow.

10. Service Reminder:

If the Odometer reading reaches below values : 450 Km, 4450 Km, 9450

Km, 14450 Km & so on after every 5000 Km up to 999450 Km (If prior

reset is not done). It should continue the same sequence above even

after roll over.

11. Side Stand :

Active Low (Vin < 0.5V)

Frame Number Location

On LH Side of Steering Tube

(Alpha-Numeric - 17 Digits)

Engine Number Location

On LH Side Crankcase Near Gear

Change Lever (Alpha-Numeric - 11 Digits)

The Frame and Engine serial numbers are used to register the motorcycle. They are the unique alpha-

numeric codes to identify your particular vehicle from others of the same model and type.

Chassis Number & Engine Number Location

Identification

I Read ..... I Learn

3

Bajaj Discover 125 UG Training Notes

Salient Features

ENGINE:

BRAKES & TYRES:

FRAME:

Features :-

• 124.5 cc Engine.

• 4 stroke, Air cooled, Single Cylinder, SOHC, DTS-I

• 11 Ps @ 7500 rpm & 11 Nm @ 5500 rpm

• Cellulose-based clutch for easy gear shifts.

Benefits :-

• Most fuel efficient bike.

• Better drive-ability and the beat fuel economy.

• Easy maneuverability during traffic.

Features :-

• 200 mm dia front brake disc and 130 mm dia rear brake drum.

Benefits :-

• Spider mug-wheels

Features :-

• Telescopic front fork with anti-friction bush & 140 mm stroke.

• Nitrox rear suspension with 120 mm wheel travel.

Benefits :-

• 16% longer travel vs. competition bike.

• Superior comfort, even on bad roads.

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Salient Features

STYLE & COMFORT:

Features :-

• Youthful Styling.

• Dual texture seat fabric with stitch line.

• Modern Side Panels.

• Enhanced Comfort.

• Dual-textured seat with stitch-line.

• Enhanced cushion for greater riding comfort.

ELECTRICALS:

Features :-

• DC Head Lamp with 12V, 35/35W, (Halogen)

• Double LED DRL headlamps

• Textured Tail-lamp Bezel

• 12V-5Ah MF Type (Electric Start)

Benefits :-

• Bold, head-turner.

• ‘Invented Horns’, makes a statement even from a distance.

• Lower battery power consumption, leading to higher mileage.

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Bajaj Discover 125 UG Training Notes

Salient Features

I Read ..... I Learn

ELECTRICALS:

Features :-

• Full Function Digital Instrument Cluster.

• Digital speedometer for accurate speed reading.

• Back-lit Display adds style and ease of reading.

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Technical Specifications

Engine & Transmission

Chassis & Body

Type : 4 stroke, Air cooled, Single Cylinder, SOHC,

DTS-I

No. of cylinders : Single

Bore : 52.0 mm

Stroke : 58.60 mm

Engine displacement : 124.5 cc

Compression ratio : 9.8 : 1

Idling speed : 1400 ± 100 in warm condition

Max. net power : 11 Ps @ 7500 rpm

Max. net torque : 11 Nm @ 5500 rpm

Ignition system : Load based CDI controlled

Carburettor : VM20 (UCAL)

Spark plug : Champion PRZ9HC & BOSCH UR4AC (Resistive)

Spark plug gap : 0.7 to 0.8 mm.

Lubrication : Wet sump, Forced lubrication

Primary resuction : 3.57 : 1 (75/21)

Gear ratios 1st Gear : 2.83 : 1 (34/12)

2nd Gear : 1.824 : 1 (31/17)

3rd Gear : 1.333 : 1 (28/21)

4th Gear : 1.087 : 1 (25/23)

5th Gear : 0.909 : 1 (20/22)

Final drive ration : 3.0 : 1 (42/14)

Transmission : 5 Speed Constant mesh (1D 4UP)

Frame Type : Semi double cradle frame

Suspension Front : 140 mm Fork travel, Telescopic

Rear : 120 mm Rear Wheel travel, Nitrox (Gas filled)

Brakes Front : Hydraulic operated, 200 mm dia. disc

Rear : Mechanically expanding shoes, 110 mm dia. drum

Tyres Front : 2.75 X 17

Rear : 100/90- 17

2

Tyre Pressure Front : 1.75 Kg/cm (25 PSI)

2

Rear (Solo) : 2.00 Kg/cm (28.5 PSI)

2

Rear (with Pillion) : 2.25 Kg/cm (32 PSI)

Rims Front : 1.4 X 17" Die Cast Aluminium Alloy Wheel

Rear : 2.15 X 17" Die cast Aluminium Alloy Wheel

Fuel Tank Capacity : 8.0 Liters

Usable Reserve : 1.5 Liters

Unusable Reserve : 0.8 Liters

Speedometer : Digital

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Bajaj Discover 125 UG Training Notes

Technical Specifications

Electricals

System : 12 Volt (DC)

Battery : 12V-5Ah MF Type

Head Lamp : 12V, 35W / 35W, HS-1 (Halogen),Blue ting DRL

Watts 5.4 & Position lamp is 0.4 Watt.

Stop / Tail Lamp : 12V, 5W / 21 W

Side Indicator Lamp : 12V, 10W (4 Nos. - RY 10W)

Position Lamp : DRL

Rear No. Plate Lamp : 12V, 3W

Speedometer Lamp : LED

Neutral Indicator : LED

Turn Signal Indicator : LED

Hi-beam Indicator : LED

Reserve indicator : LCD

Fuel Gauge : LCD

Horn : 12V, DC

Grade : 20W50 API SL / JASO MA

Drain & Refill : 1000 ml

Overhaul : 1100 ml

Notes :

• Values given above are nominal & for guidance only, 15% variation is allowed

to cater for production & measurement.

• All dimensions are under un-laden conditions.

• Definitions of terminologies wherever applicable are as per Relevant IS/ISO

standards.

• Specifications are subject to change without notice.

Dimensions

Weights

Engine Oil

Length : 2035 mm

Width : 760 mm

Height : 1085 mm

Wheel Base : 1305 mm

Saddle height : 805 mm

Turning Circle Radius : 2100 mm (min)

Ground Clearance : 165 mm

Vehicle Kerb Weight : 122 Kg.

Gross Vehicle Weight : 252 Kg.

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Pre Delivery Inspection Check List

1. Check points before starting of the vehicle

Check & correct the below check points before starting the vehicle

To Check Check for

? If Ok

X If Not Ok

Engine oil Oil level between lower & upper mark / Top up if required

Fuel tank / pipes

No leakage / Correct fitment

Mirror

Fitment & adjustment to ensure clear rear view

Lock Operation Steering cum Ignition lock, LH side cover lock, Petrol tank cap lock

Battery

Check battery Terminal voltage. Fully charged battery voltage should be >

12.4 V DC. Charge battery if required using recommended battery charger.

Tightness of battery terminals / cables / Petroleum Jelly application

Tyre Pressure

Front: 1.75 kg/cm (25.0 psi)

Rear: 2.25 kg/cm (32.0 psi)

Brakes

Front brake cable free play 4 ~ 5 mm

Rear brake pedal free play 20 ~ 25 mm

Clutch cable

Free play 2 ~ 3 mm

Drive chain

Slackness 25 ~ 30 mm

Equal marking of chain adjusters on both side

No touching to chain case after adjustment.

Fasteners (Check torque)

Recommended torque wrench

to be used for applying torque

on nut - bolts as mentioned in

PDI check sheet using

reference torque chart as

given.

However, if any major parts are

required to be removed (Except

side cover & seat) for

accessibility of torque wrench, in

those cases the tightness can

be ensured using open end /

ring spanner / box type spanner

as applicable without removing

those major parts

Engine foundation bolts - Front 1.8 to 2.2 Kg.m

Engine foundation bolts - Rear 2.8 to 3.2 Kg.m

Engine foundation bolts - Top 1.8 to 2.2 Kg.m

Front Axle Nut 4.5.0 to 5.5 Kg.m

Rear Axle Nut 8.0 to 10.0 Kg.m

Front Fork top bolts 3.0 to 3.2 Kg.m

Front Fork under bracket bolts 3.0 to 3.2 Kg.m

RSA mounting nut (Upper) 3.0 to 3.2 Kg.m

RSA mounting nut (Lower) 2.8 to 3.2 Kg.m

Swing arm shaft nut 4.5 to 5.5 Kg.m

Rider Foot Rest Mounting 1.8 to 2.2 Kg.m

LH & RH Pillion stay Bolts 1.8 to 2.2 Kg.m

Ço Check Check for

? If Ok

X If Not Ok

9

Bajaj Discover 125 UG Training Notes

Pre Delivery Inspection Check List

I Read ..... I Learn

2. Check points during / after starting the vehicle

Check & correct the below check points during / after starting the vehicle

Switch operation

RH & LH control switch, ignition switch, clutch switch & brake switch (Front &

Rear)

Horn Ensure no distorted sound

All Bulbs working Headlight, Tail / Stop lamp, Side indicators, Speedo bulbs, Number plate bulb

Speedometer

(As applicable)

Working of speedometer, Odometer, Fuel gauge.

Working of all signal indicators icons (Neutral, Turn signal, High beam)

Headlamps Focus confirmation

3. Check points during Test ride

Check & correct the below check points during Test ride

Gear shifting Smooth operation

Drive-ability

Throttle response

Brake effectiveness - Front & Rear

Engine noise No abnormal noise

Front fork / steering

Smooth working by pumping movement & smooth operation (No play / No

Sticky movement)

Oil leakages Specify source of leakages & rectify if any.

4. Idling RPM / CO%

Check & correct the below check points in engine warm condition

Idling RPM

(Engine warm up

condition)

SAI connected – 1350 to 1450 rpm (@ 60°C)

SAI disconnected – 1300 to 1400 rpm (@ 60°C)

CO% Check

SAI connected - < 1% (@ 60°C at idling rpm)

SAI disconnected – 4.0% to 5.0% (@ 60°C at idling rpm)

5. Visual inspection for dent, scratches, rust ...

6. Clean the vehicle thoroughly before delivery to customer.

Periodic Maintenance & Lubrication Chart

      

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Sr

No

PM Check Point

Recommended Frequency

Remark

Service

1st

2nd

3rd

4th

5th

6th

7th

Kms

500

4500

9500

14500

19500

24500

29500

~

750

5000

10000

15000

20000

25000

30000

1

Servicing with water wash

Ensure to prevent water

entry in Petrol tank,

Silencer & electrical parts.

Use caustic free detergent

for washing.

2

Engine oil (Bajaj DTSi 10000 oil) &

engine oil filter*

C,R

R

T

op

Up

R

Top

Up

R

T

op

Up

R

"BGO DTS-i 10W30 for 100cc

models. BGO DTS-i 20W50 for

models above 125cc. "

3

Oil strainer, Body centrifugal filter**

CL

Oil strainer cleaning at the time

of

oil

change.

Clean body

centrifugal

filter at

1st

free

service

&

at 20,000 kms

4

Starter Clutch (Dry

Type)**

L

Use recommended molycote

grease

5

Spark plug

CL,A,R

CL,A

R

6

Air Cleaner Element *** & Cover "O" Ring

CL,R

CL

R

CL

R

Foam & Paper as applicable.O ring

check at every service & Replace if

cut/damaged

7

In line paper filter or Fuel cock paper filt er

R

8

Fuel cock sediment bowl cleaning

CL

9

Carburetor rubber duct

C,R

Check & replace if required

10

Fuel pipe

C,R

C

R

C

R

1

V

alve tappet clearance

C,A

12

Non-Sealed drive chain cleaning &

lubrication

CL,L,A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

• During

1st

free

service

: Use

lint

free cloth

for cleaning &

SAE

90 oil

for

lubrication

without removing

from vehicle.

(If chain

is excessively dirty, then

chain

has to

be

removed, cleaned

using

diesel &

lubricated

using

mo

l

te

n

I

OC

se

r

v

o

c

o

mp

o

u

nd

chain

grease.)

• Dur

ing

all o

th

e

r

ser v

i

c

e

s:

R

emo

v

e

, c

l

e

a

n u

sin

g

d

i

esel

&

l

u

br

icate

d u

sing

mo

l

t

en

cha

i

n

grease.

13

Sealed drive chain cleaning & lubrication

CL,L,A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

CL,L,

A

•

During

regular

service

use

OKS

s

pra

y

f

o

r

c

h

ain c

lean

in

g

,

w

i

t

ho

u

t

removing chain

from vehicle.

• If chain is

excessively dirty,

then

chain

has

to

be

cleaned

by

removing

from vehicle.

(Customer to

apply

OKS chain

lube

spray at

every 500 Kms)

14

Engine air breather tube

C

Replace if damaged

15

Silencer drain hole cleaning

CL

16

Silencer tail pipe cleaning **

CL

17

Brake lining or pad wear & lubricate brake

cam & pivot pin** Check pad wear indicator

C,L,R

C

C,L,R

R

C,L,R

R

Replace brake shoe/pads at

every 15,000 kms

Periodic Maintenance & Lubrication Chart

* It is strongly recommended to use only Bajaj genuine oil, in case of any other engine oil of same specification is used the would be every 5000 kms

** As applicable to model

*** more frequent cleaning is required while driving in dusty environment

C: Check, A: Adjust, CL: Clean, R: Replace, T: Tighten, L: Lubricate

Note :- Periodic parts / lubricants as per periodic maintenance & Lubrication chart are mandatory & the same is chargeable to customer

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Bajaj Discover 125 UG Training Notes

I Read ..... I Learn

Sr

No

PM Check Point

Recommended Frequency

Remark

Service

1st

2nd

3rd

4th

5th

6th

7th

Kms

500

4500

9500

14500

19500

24500

29500

~

750

5000

10000

15000

20000

25000

30000

18

Brake fluid level ** - top up / replace

C,A,R

C,A

R

Use recommended

DOT

3/4 brake fluid

19

Disc brake assembly–-check functionality

,

leakage or any other damage

C

Replace if damaged

20

All cables & rear brake pedal - free play

C,A

21

Battery electrolyte level , specific gravity

C,A,T

Not applicable for VRLA

batteries

22

Wiring harness & battery connection -

routing, tie bands & clamps tightness

C,A,T

C,A,

T

C,A,T

23

Ignition switch barrel cleaning & handle bar

control switches contacts cleaning

C,CL

Use recommended Wd40

spray

24

Steering play

C,A

25

Steering stem bearing *** & cap steering

bearing (Plastic)**

C,CL,

L,R

C,CL,

L,R

C,CL,

L,R

C,CL

Check & replace if

damaged.Use HP

Lithon

RR3 grease for lubrication

26

Main stand & side stand pin **

CL,L

Use recommended AP

grease

27

Swing arm pivot pin

(For non silent bush)**

L

Not applicable in case of

needle roller bearing

28

All fasteners tightness

C,T

29

Engine foundation silent bushes **

C

Replace if damaged

30

General lubrication - clutch lever

, front brake

lever

, kick lever

L

Use recommended

AP

grease

31

Idle speed / CO%

C,A

32

Coolant level in expansion tank

**

C,A

R

Use recommended 'Ready

to Use coolant'.Replace at

every 30000 Kms or 2

years (Whichever occurs

earlier)

33

Coolant hose damage / clamps / leakage **

C

Check & replace if required

34

Radiator fins **

C

Check & replace if required

35

Spoke tightening ** - Front & Rear

C,T

36

Front fork dust seal area & inner pipe

cleaning**

CL

Applicable for front fork

with rubber bellow

37

SAI system / EV

AP

hoses - Check functionality

,

leakage or any other damage**

C, R

Replace if cut / damaged

38

Pillion foot rest hinge lubrication**

L

Use RR 3 Grease

39

EVAP

Y

connector drain tube

CL

Notes

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Fuel System

CHAPTER 2

Carburettor Specifications

Overview of Fuel System

Secondary Air Induction (SAI) System

Evaporative Emission System

Tune-up for Optimum Mileage

13

Bajaj Discover 125 UG Training Notes

Key Learning Points

Understanding of

Carburettor

Understanding of CO checking procedure

and Tune-up for optimum mileage

Understanding of SAI system

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Bajaj Auto International Business

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Fuel System

Carburettor Specifications

Item Specification

Make UCAL

Type UVD 20

VC Screw Setting 2.5± 1.5

Idling Speed 1400 ± 100 rpm

Main Jet 102.5

Jet Needle ‘e’ clip Position Single

Jet Needle Marking JN

Pilot Jet 17.5

Float Height 14.4 mm

Starter Jet 30

Choke

Throttle valve mark

Manual

CA

Overview of Fuel System

Fuel System

15

Bajaj Discover 125 UG Training Notes

Hose to Intake SAI

Carburettor

Intake Manifold

Hose to Manifold

SAI System

Drain Tube

Breather Tube

Air Filter

Secondary Air Induction (SAI) System

Hose Pipe Connecting

Air Filter to SAI

Hose Pipe Connecting

SAI to Cylinder Head

Hose Pipe Connecting

Intake Manifold to SAI

SAI Unit

ON Acceleration ON De-acceleration

Function:

To reduce the concentration of exhaust gases in exhaust system thus reducing the emission.

Construction:

• Consists of diaphragm valve and reed valve.

• Connected to air filter assembly, exhaust valve passage in the cylinder head and intake manifold.

Secondary Air Induction (SAI) System :

Air Inlet

Air outlet

Vaccum In

Engine vacuum

pulling diaphragm

No fresh air

supply to

Exhaust manifold

Air Inlet

Air outlet

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Fuel System

Secondary Air Induction (SAI) System

Working:

On Acceleration

During the exhaust phase of the engines operation, exhaust gases enter the exhaust system at high velocity.

This Causes a drop in the pressure which enables the reed valve to open.

• Fresh and filtered air from air filter is inducted in the exhaust passage, just after the valve.

• The oxygen in the air enables ‘CO’ to further oxidize and convert into ‘CO2’ & HC into H2O. Thus CO

(%) & HC (ppm) at the Silencer tail end is reduced. This results in reduction of exhaust emission.

• The read valve opening and closing is based on pressure in the exhaust system.

On De-acceleration

When throttle is closed, some amount of fuel particles get discharged into the exhaust. If air is injected into

the Exhaust system at this point of time, these fuel particles can get ignited. This causes after burn or

misfiring sound in the exhaust system.

• To avoid this, air flow is momentarily stopped by closure of the diaphragm in the injection valve during de-

acceleration.

How Diaphragm Works:

• Diaphragm is connected to inlet manifold.

• On de-acceleration vacuum increases in the manifold.

• This pulls the diaphragm against the spring tension and restricts the air flow.

• Once the vacuum reduces the diaphragm opens due to spring tension and air starts flowing.

Advantages:

• Reduced emission of Carbon Monoxide & Hydro Carbons.

• Environment friendly vehicle.

Fuel System

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Bajaj Discover 125 UG Training Notes

Evaporative Emission System

Working:

EVAP is a evaporative Emission system which prevents fuel vapours going to atmosphere by converting fuel

vapours into fuel droplets through canister.

These fuel droplets are feed to engine through one way mechanically operated Purge valve.

Tank Port

Purge

Port

Drain Port

Breather

Port

Out Port

In Port

Function of canister:

The canister is filled with about a pound or two of activated

charcoal. The charcoal acts like a sponge and absorbs and

stores fuel vapours. The vapours are stored in the canister

until the engine is started, warm and being driven.

Working Principle of EVAP System:

A passage is provided from tank to canister through tank cap. This passage aids in breathing as well as passing

HC vapours to canister. Canister acts as storage for these vapours and these vapours are purged to engine

through purge valve due to manifold suction in vehicle.

Purge valve:

Purge valve is one way valve which controls the

flow of HC vapours from canister to carburettor.

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Fuel System

Tune-up for Optimum Mileage

a. Ensure no fuel leakage through fuel

cock, fuel lines.

b. Ensure free rotation of both wheels.

c. Ensure correct tyre pressure -

Front wheel : 25 PSI,

Rear (Solo) : 28.5 PSI

Rear (Pillion) : 32 PSI

c. Check and confirm proper functioning

of spark plug.

d. Use of recommended grade of bajaj

genuine oil & engine oil level between

MIN & MAX level.

e. Set control cable free play:

• Clutch lever 2~3 mm.

• Rear brake pedal 20 ~ 2

5 mm.

f. Chain slackness : 25 ~ 30 mm.

COMPRESSION PRESSURE

• Standard :

2

12 to 13 Kg/cm

• Service Limit :

2

9.5 Kg/cm

FOAM FILTER:

• Clean at Every :

5000 Kms.

• Replace at Every :

15,000 Kms.

CARBURATTOR

• Idling : 1400 + 100 rpm.

• Jet Needle Clip Position:

Single groove

• VC Screw Setting :

2.5 ± 1.5

TAPPET CLEARANCE

• Inlet Valve :

0.05 ~ 0.07 mm

• Exhaust Valve :

0.10 ~ 0.12 mm

SPARK PLUG :

• Spark Plug Gap :

0.7 ~ 0.8 mm.

• Replace at Every :

30,000 Kms

Engine Tune up Other Mandatory Checks

0.7 to

0.8 mm

Fuel System

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Bajaj Discover 125 UG Training Notes

Notes

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Bajaj Auto International Business

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Fuel System

Engine & Transmission

CHAPTER 3

21

Bajaj Discover 125 UG Training Notes

Key Learning Points

Appropriate torque application for various

engine component

Standard operating procedure for

engine dismantling

Understanding of lubrication path

in engine

Special Tools

Engine Removal from Frame

Engine Dismantling & Assembling

Service Limits

Tightening Torque

Engine Lubrication Flow of Oil

Dos & Don’ts

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Bajaj Auto International Business

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Engine & Transmission

Special Tools

Cam Sprocket Holder

Part No. : 37 10DH 36

Application : For holding cap sprocket,

during removal & re-fitment.

LH Spark plug removal

Part No. : 37 2540 34

Application : For removing LH spark

plug from cylinder head.

Magneto Rotor Puller (For Self Start)

Part No. : F4 1ZJZ 10

Application : To pull out the rotor from

crankshaft assembly.

Adapter & Valve Spring Compressor

Part No. : Adapter : 37 1031 08

Part No. : Valve Spring Compressor :

37 1031 07

Application : To assemble / dismantle

intake, exhaust valve by compressing

spring in cylinder head.

Rocker Shaft Remover

Part No. : 37 10DH 35

Application : To remove Rocker Shaft

from cylinder head.

23

Bajaj Discover 125 UG Training Notes

Special Tools

Bearing Driver Set

Part No. : 37 1030 61

Application : For pressing bearings in

crankcase.

Input Shaft Bearing Extractor

Part No. : 37 10DJ 01

Application : To Pull out main ball

bearing from crankshaft, steering races

from fork under holder bracket.

RH Spark Plug Removal Tool

Part No. : 37 1040 51

Application : For removing RH spark

plug.

Piston Pin Removal Tool

Part No. : 37 1010 06

Application : For removing piston pin

from piston.

Engine Temperature Sensor Removal

Tool

Part No. : 37 1043 46

Application : For removing & fitting

Engine temperature sensor.

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Special Tools

Primary Gear Holder

Part No. : F4 1AJA 11

Application : To hold primary &

secondary gear while loosening /

tightening the primary gear nut and

special nut securing clutch.

Valve Tappet Adjuster

Part No. : F4 1ZJW 33

Application : To hold the Valve Tappet

screw while adjusting tappet clearance.

Output Sprocket Holder

Part No. : 37 1030 53

Application : To hold the output

sprocket while removing sprocket allen

bolts.

25

Bajaj Discover 125 UG Training Notes

Engine Removal from Frame

Pull out :

• Rubber cap of thermal sensor.

Remove :

• Ring terminal using 8 mm

spanner.

• Carburetor assembly.

Remove

• S t a t o r p l a t e c o u p l e r

connections.

• Neutral switch connection.

• Remove spark plug caps.

Pull out :

• Starter motor wire rubber cap.

Remove :

• Starter motor connection.

Remove :

• Kick lever mounting bolt.

• Take out kick lever.

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Removal from Frame

Remove

• Engine mounting rear bottom.

• Take out engine assymbly.

Remove :

• Clutch cable mounting bolts.

• Take out bracket clutch cable.

• Earthing connection.

Pull out :

• SAI hose clips.

Take out

• SAI hose from intake manifold.

• Engine breather pipe from

cylinder head.

Remove

• Silencer mounting front bolt.

27

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• Cylinder head cover bolts

• Take out cylinder head cover &

gasket.

Note - Always loosen cylinder Head

mounting bolts in criss - cross pattern

Remove

• TDC finder cap

• Check the cam sprocket T

mark.

Note - Align the rotor mark w.r.t

Crankcase marking.

Remove

• Cam chain tensioner bolt

• Rotate chain tensioner screw in

clockwise direction to take

plunger backwards and lock it.

Remove

• Chain tensioner

• Take out chain tensioner along

with gasket.

Top Side Dismantling

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Dismantling & Assembling

Remove

• Cam sprocket bolt

Skill Tip: Using Cam Sprocket

Holder Special tool to hold the cam

sprocket

Remove

• Cam sprocket

• Cam sprocket collar

Remove

• RH & LH side spark plug by

using spark plug removing tool.

Remove

• Spark plug sleeve using

Note : Do not pull spark plug sleeve by

plier, to avoid any damage on it.

Remove

• Cylinder head bolts.

1

st

29

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• Cam sprocket Circlip

• Circlip of rocker arm shaft (Inlet

& Exhaust)

Remove

• Rocker arm shaft (Intake &

Exhaust) by using rocker shaft

removing tool

• Take out rocker arm & rocker

arm shaft.

Skill Tip: Using Rocker Shaft

Removal Special tool to remove

the Rocker Arm Shaft.

• Take out cam shaft assembly.

Skill Tip: Using Adaptor & Valve

Spring Compressor Special tool to

compress the valve springs.

Remove

• Intake & Exhaust valves along

with -

- Retainer

- Valve spring

- Oil seal

- Valve spring seat using valve

spring compressor.

Remove

• Dowels on cylinder block.

• Cylinder head gasket.

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Dismantling & Assembling

Remove

• Chain guide.

• Cylinder block.

Remove

• Dowels.

• Cylinder block gasket.

Remove

• Piston pin locking clip

• Piston pin

• Take out piston.

Note - Cover the crankcase bore with

clean cloth before removing piston pin

locking clip.

Remove

• Engine oil filter cover

• T spanner & take out engine oil

filter

Clutch Side Dismantling

31

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• Clutch cover mounting

• Spanner & take clutch release

shaft

• Clutch cable bracket.

Remove

• Clutch thrust bearing

• Primary gear nut with by using

clutch nut removing special

tool.

• Clutch nut by holding the

primary gear.

Note - Lock the special tool between

primary gear teeth & clutch housing gear

from top.

Remove

• Clutch nut

• Belleville washer

• Plain washer

Remove

• Clutch stack complete

• Plain washer

Skill Tip:

1. Using Primary Gear Holder Special tool to hold the primary gear.

2. Using Clutch Nut removing tool to loosen / tighten special nut securing clutch.

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Dismantling & Assembling

Remove

• Kick return spring

• Take out kick shaft assembly.

Remove

• Lever comp gear shift

Remove

• Inhibitor Assembly

• Guide gear shift

• Take out guide gear shift

Remove

• 4 bolts

• 4 springs

• Clutch holder

• Clutch hub

• Friction plates

• Steel / pressure plates (4 Nos)

• Wheel clutch

Skill tip: Using Clutch Dismantling

tool to dismantle & assembled

clutch.

33

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• Oil pump driven gear

• Oil pump screws

• Take out the oil pump

Remove

• Primary gear nut

• Take out

- Belleville washer

- Plain washer

- Primary gear

Remove

• Timing chain from sprocket

• Starter motor bolt

• Take out starter motor

Remove

• Magneto cover bolts

Magneto Side Dismantling

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Dismantling & Assembling

Remove

• Stator plate

• Pick up coil screws

Remove

• Dowels

• Take out magneto cover

gasket.

Remove

• Gear starter clutch locking plate

screw

• Rotor bolt

• Plain washer

Remove

• Rotor

• Gear starter clutch

Remove

• Magneto rotor key

• Starter counter gear assembly

Skill Tip: Using Magneto Rotor

Puller Special tool to remove

magneto rotor from crankshaft.

35

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• LH crankcase bolts

• RH crankcase bolts

• Put the engine on engine work

table

Remove

• RH crankcase

Remove

• Crankshaft

t• Fork shaft

• Input & output fork shaft

Remove

• Gear change drum

• Input fork & output fork

Crankcase Splitting

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Engine Dismantling & Assembling

Remove

• Input & output gear shaft

assembly

• washer plain of input gear

shaft.

Remove

• Crankshaft damper from

crankcase LH.

Remove

• Input shaft bearing locking

plate

• Kick shaft locking plate bolts

Remove

• Input shaft bearing using

bearing driver set.

Remove

• Bolt gear shift change

• Gear change drum bush using

bearing driver set.

37

Bajaj Discover 125 UG Training Notes

Engine Dismantling & Assembling

Remove

• Output shaft oil seal

• Gear change lever oil seal

Remove

• Output shaft bearing using

bearing driver set

• Neutral switch

Engine & Transmission

Service Limits

Serv. Limit

67.6

18.071

Inlet

18.02

Std. Limit

Serv. Limit

18.104

Exhaust

18.05

Cam Height

130.3 ~ 130.43

Std. Limit

Serv. Limit

131.06

Cam Chain 20 Links Length

20-link length

1st 2nd 21st

MEASURE THIS LENGTH

Valve Clearance

0.05~0.07

Inlet

----

Std. Limit

Serv. Limit

0.10~0.12

Exhaust

----

0.01

Std. Limit

Serv. Limit

> 0.01 replace

Valve Stem Bend

Piston Ring End Gap

0.1~0.25

TOP

0.5

Std.Limit

Serv.Limit

0.15~0.3 0.2~0.7

SECOND OIL RING

0.6 1.0

Friction Plate Thickness

2.95 ~ 3.05

Std. Limit

Serv. Limit

2.75

10.0

Std. Limit

Serv. Limit

9.965

Rocker Arm Shaft Dia.

4.965~4.98

Inlet

4.955

Std. Limit

Serv. Limit

4.945~4.96

Exhaust

4.935

Valve Stem Diameter

Cylinder Head Warp

2

12.0 ~ 13.0 Kg/cm

Std. Limit

Serv. Limit

2

9.5 Kg/cm

Compression Pressure

Cam Sprocket Root Diameter

68.0

Std. Limit

 1.55 ~1.65

1.5

Std. Limit

Serv. Limit

Steel Plate Thickness

0.03

Std. Limit

Serv. Limit

0.05

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Bajaj Auto International Business

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Engine & Transmission

ALL DIMENSIONS ARE IN MM

Piston Diameter

51.958 ~ 51.972

Std.

Limit

Serv.

Limit

----

0.028 ~ 0.052

Std. Limit

Serv. Limit

0.1

Piston / Cylinder Clearance

37.5

Serv. Limit

Shift Drum Groove Width

Std. Limit

Serv. Limit

4.55 ~ 4.70

4.75

Piston Ring / Groove Clearn.

0.025~0.060

TOP&SECOND

0.15

Std. Limit

Serv. Limit

0.04~0.010

OIL

0.16

43

Serv. Limit

Cylinder Inside Diameter

10mm

20mm

40mm

----

Std. Limit

Serv. Limit

50 ~ 50.01

Valve Spring Free Length

38.74

Std. Limit

Clutch Spring Free Length

 44~46.4

Std. Limit

0.1

Std. Limit

Serv. Limit

0.2

4.45 ~ 4.49

Std. Limit

Serv. Limit

4.40

Gear Shift Fork Guide Pin Dia.

Pressure Plate Warp

Service Limits

39

Bajaj Discover 125 UG Training Notes

Engine & Transmission

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Bajaj Auto International Business

3

Engine & Transmission

Tightening Torques

6.0 ~ 6.5 Kgm.

Clutch Cover Bolts

0.6 ~ 0.8 Kgm.

Output Sprocket Bolts

1.0 ~ 1.1 Kgm.

Cylinder Head Cover Bolts

1.0 ~ 1.1 Kgm.

Chain Tensioner Mounting Bolts

Crankcase Joining Bolts

1.0 ~ 1.1 Kgm.

M8 : 2.3 ~ 2.5 Kgm.

Cylinder Head Bolts

6.5 ~ 7.0 Kgm.

Cap Oil Filter Cover Bolts

1.0 ~ 1.1 Kgm.

Inhibitor Nut

Stator Motor Mounting Nut

Clutch Nut (L.H. Thread)

0.5 ~ 0.7 Kgm.

Oil Pump Screws

1.0 ~ 1.1 Kgm.

Magneto Rotor Mounting bolt

Cam Sprocket Allen Bolt

1.6 ~ 1.8 Kgm.

1.0 ~ 1.1 Kgm.

Magneto Cover Bolts

1.0 ~ 1.1 Kgm.

Manifold Mounting Bolts

1.0 ~ 1.1 Kgm.

Tightening Torques

Spark Plugs

1.8 ~ 2.2 Kgm.

Engine Mounting Nut - Front

1.0 ~ 1.1 Kgm.

Oil Drain Bolt (18 mm A/F)

1.3 ~ 1.5 Kgm. 2.8 ~ 3.2 Kgm

Engine Mounting Nut - Rear

Drum / Cam Allen Bolt

1.0 ~ 1.1 Kgm.1.8 ~ 2.2 Kgm.

Engine Mounting Nut - Top

41

Bajaj Discover 125 UG Training Notes

Engine & Transmission

INLET

PASSAGE

Outlet hole of paper filter chamber

Clutch cover passage

Oil

plunger

RH side

crankcase

hole

Paper oil filter

Clutch cover oil passage

Inlet hole of paper filter chamber

RH side crankcase oil passage

Oil pump outlet

Oil pump inlet

Oil strainer

Engine Lubrication - Flow of Oil

OUTLET

towards

crankshaft

towards

Crankcase RH

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Bajaj Auto International Business

3

Engine & Transmission

Engine Lubrication - Flow of Oil

Crank big end pin

through crankshaft

drilled hole

Con rod slots

Two fountains for

lubricating cylinder

piston parts

LH side

crankcase passage

Crankcase LH hole

Gap between bolt

and cylinder block

& cylinder head

L.H. Crankcase

passage towards

nozzle

Nozzle

oil jet

Towards block

43

Bajaj Discover 125 UG Training Notes

Engine & Transmission

Don’ts

Dos & Don’ts

Dos

Always replace

gasket ‘O’ rings of

engine If dismantled.

Do not reuse ‘O’

rings, gasket, Oil

seals, Circlip, Springs

& locks as they use

their strength &

properties, once they

are opened.

Whenever installing

Spark Plug, first

screw by hand &

then tighten to

specified torque.

0.7 to

0.8 mm

Do not adjust spark

plug electrode gap

by hacksaw blade or

with judgment of eye

otherwise it will affect

the engine

performance.

Always set / adjust

valve tappet

clearance in engine

cold condition.

Do not set valve

tappet clearance in

engine hot condition.

Do not reuse torn

‘Oil strainer’

otherwise it will affect

lubrication system of

engine &

subsequently would

lead to seizure.

Always below light

pressure compressed

air from inside while

cleaning ‘Oil strainer’

that is opposite to

the direction of flow

of oil.

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Bajaj Auto International Business

3

Engine & Transmission

Notes

45

Bajaj Discover 125 UG Training Notes

Engine & Transmission

Frame & Suspension

CHAPTER 4

Special Tools

Service Limits

Tightening Torque

Dos & Don’ts

46

Bajaj Discover 125 UG Training Notes

Key Learning Points

Appropriate torque application for

various Frame component

Understanding of special tools and

its applications

Standard operating procedure

47

Bajaj Auto International Business

4

Frame & Suspension

Special Tools

Fork Oil Seal Extraction Tool

Part No. : 37 0043 25

Application : For extracting front fork oil

seal from outer tube.

Fork Seat Pipe Holder

Part No. : 37 0043 20

Application : For holding fork seat pipe

during outer tube bottom bolt removal.

Steering Slotted Nut Special Tool

Part No. : 37 0043 02

Application : To remove / tighten

steering slotted nut.

Fork Oil Seal Driver

Part No. : 37 1830 07

Application : To fit fork oil seal in its

seat provided at outer pipe ID.

Stem Bearing Driver

Part No. : 37 1830 05

Application : To fit bearing race on fork

under holder bracket.

Frame & Suspension

48

Bajaj Discover 125 UG Training Notes

Special Tools

Front Fork Inner Tube Extractor

Part No. : 74 9310 15

Application : To remove front fork inner

tube from outer tube.

Installer Upper & Lower Bearing race

Frame

Part No. : 37 1801 06

Application : To install upper & lower

steering races / cones into their seats

inside frame.

Steering Cone Remover

Part No. : 37 1805 06

Application : To remove steering cones

from frame.

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Bajaj Auto International Business

4

Frame & Suspension

Service Limits

Brake Panel Cam Hole Dia.

Std. Limit

Ser. Limit

12.15

12.00 ~ 12.027

Brake Cam Front Diameter

Std. Limit

Ser. Limit

11.83

11.957 ~ 11.984

Std. Limit

Ser. Limit

130 ~ 130.16

130.75

Brake Drum Inside Dia. Rear

Brake Shoe Rear Liner Thickness

Std. Limit

Ser. Limit

3.9 ~ 4.5

2.0

Front Fork Spring Free Length

Std. Limit

Ser. Limit

Free Length

Axle Run Out

Axial Wheel Run Out

Std. Limit

Ser. Limit

TIR 0.5 or Less

TIR 2.0

Radial Wheel Run Out

Std. Limit

Ser. Limit

Drive Chain 20 Link Length

254 ~ 254.6

260.0

Std. Limit

Ser. Limit

20 Link Length

1st 2nd 20th

MEASURE THIS LENGTH

Rear Sprocket Warp

TIR 0.4 or less

TIR 0.5

Std. Limit

Ser. Limit

446.5

441.5

Std. Limit

Ser. Limit

TIR 0.1

TIR 0.2

TIR 0.5 or Less

TIR 2.0

25 ~ 30

Drive Chain Slack

Std. Limit

Rear : 6.5, Front : 5.0

Upto TWI

Std. Limit

Ser. Limit

45

Ser. Limit

Tyre Tread Depth

Tightening Torques

4.5 ~ 5.5 Kgm

Front Axle Nut

Rear Sleeve Nut

4.5 ~ 5.5 Kgm

Front Fender Mounting Bolts

0.8 ~ 1.2 Kgm

Rider Foot Rest Mounting

1.8 ~ 2.2 Kgm

8.0 ~ 10.0 Kgm

Rear Axle Nut

Torque Rod Nut

3.0 ~ 3.2 Kgm

Rear Sprocket Mounting Nut

Handle Bar Holder Bolts

2.0 ~ 2.2 Kgm

Steering Center Nut (Slotted)

Fork Under Bracket Bolts

R.S.A. Lower Bolt

8.0 Kgm

3.0 ~ 3.2 Kgm

R.S.A. Mounting Nut Upper

3.2 ~ 3.8 Kgm

Fork Pipe Top Bolts

0.5 Kgm

Swing Arm Shaft

3.0 ~ 3.2 Kgm

2.8 ~ 3.2 Kgm

Frame & Suspension

50

Bajaj Discover 125 UG Training Notes

Don’ts

Dos & Don’ts

Dos

Replace front fork oil

with SAE 10W20

grade fork oil.

Do not add any

other mineral based

oil to front fork.

Maintain correct tyre

pressure as per

specification.

Do not over / under

inflate the tyres.

Avoid Bends /

Distortion of torque

link rod.

Check for split pin at

torque rod nut.

Do not reuse the old

swing arm Bushes /

Bearings.

Lubricate the swing

arm Bushes / Shafts.

51

Bajaj Auto International Business

4

Frame & Suspension

Notes

Frame & Suspension

52

Bajaj Discover 125 UG Training Notes

Electricals

Battery Specifications

Electrical Checking Procedures

Important SOP

Dos & Don’ts

Electrical Wiring Diagrams

53

Bajaj Discover 125 UG Training Notes

Key Learning Points

Understanding of Battery

specifications & charging procedure

Checking and inspection of all

Electrical component

Standard operating procedure for

Head light assembling and dismantling

CHAPTER 5

54

Bajaj Auto International Business

5

Electricals

Battery Specifications

Battery Technical Specification

• Make Exide / Amco

• Voltage 12 Volt

• Type MF Battery

• Capacity 5 Ah

0

• Specific gravity of electrolyte 1.24 for use above 10 C, 1.28 for use

0

for initial filling of new battery below 10 C

• Initial charging duration 13 hrs (This ensures 100% battery

Is charged).

• Charging current specification 0.5 Amp

In case battery is discharged follow the procedure given below by using constant current. “Battery Charger” of

0.5 Amp. charging current specification for 5 Ah battery

• Remove battery from vehicle

• Clean battery throughly

• Remove vent / filler plug strip

• Top up level with distilled water in between Min and Max. level

• Connect to battery charger & ensure respective terminal are connected properly

• Set charging current at 0.5 A DC for 5 Ah Battery. Charging voltage of charger should be more than 14.5

volt without connecting the battery .

• Charge battery (battery charging time depends upon the charging condition of the battery)

• Check specific gravity of each cell & voltage after 1 hour it should be 12.5 volt & specific gravity 1.24 for

the fully charged battery.

• Disconnect the battery from the changer.

• Fit vent / filler plug strip firmly.

• Reconnect battery terminals

• Apply petroleum jelly to the battery terminals.

Battery Charging Procedure

• Fill each cell with battery grade sulfuric acid of the correct sp. gravity (1.24 at room temp. for use above

0 0

10 C & 1.28 at room temp. for use below 10 C)

• Allow the battery to stand for 30 min. after filling.

• Keep vent plugs open. Connect battery to charger & charge at 0.5 Amp. Charging voltage of charger

should be 14.5 volt min. without connecting the battery.

• Charge continuously for 13 hours (charging duration will depend upon the condition of the battery) Specific

gravity of fully charge battery after rest period of 1 hour will be 1.24 & battery voltage will be 12.9 Volts.

• After charging push vent plugs strip firmly into place & wash off acid spillage with water & dry the battery.

• Using the battery load tester confirm for good indication of state of charge of battery.

Initial Charging Procedure for dry charged Battery

Electricals

55

Bajaj Discover 125 UG Training Notes

Electrical Checking Procedure

Measuring & Testing Equipment : Multimeter

Front & Rear Brake Light Switch

Brown Blue

Continuity check by multimeter

Lever/Pedal Pressed Continuity is shown

Lever/Pedal Released

No continuity

SOP :

• Turn ‘ON’ the ignition switch.

• The brake light should glow on when the front brake lever / rear

brake pedal is pressed.

• If it does not, check the front brake switch.

Measuring & Testing Equipment : Multimeter

• Check continuity of clutch switch as follows.

Clutch Switch

Black / Yellow Yellow / Green

OFF – Clutch lever not pressed

ON – Clutch lever pressed

Light Green

Measuring & Testing Equipment : Multimeter

Ignition Switch

Brown White

OFF

ON

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Bajaj Auto International Business

5

Electricals

Electrical Checking Procedure

Measuring & Testing Equipment : Multimeter

Fuel Gauge - Tank Unit

Connections

Standard Value

200 Ohms

Meter +ve Meter -ve

White / Yellow

Black / Yellow

As per chart given below

Standard Value

Note: If display in speedo console is not proper then please check following,

• Battery Voltage

• Speedometer coupler & fuel gauge tank unit coupler connection is firm.

Measuring & Testing Equipment : Multimeter

Stator Relay Inspection

Connections

Standard Value

200 Ohms

Meter +ve Meter -ve

Yellow / Red

Black

3.9 Ω ± 10%

SOP :

• Connect external 12V DC supply to Radiator relay coil terminals.

• ‘Tuk’ sound will be heard.

• Set multimeter on continuity mode.

• Connect multimeter at to relay contact terminals.

• Continuity (beep sound) indicates Radiator relay is OK.

Meter Range

Fuel Level Fuel Quantity(L) Standard Value(

O

)

Empty Tank

1.4 98

Half Tank

5 45

Full Tank

8 8

Electricals

57

Bajaj Discover 125 UG Training Notes

Electrical Checking Procedure

Measuring & Testing Equipment : Multimeter

Engine Thermal Sensor

Connections

Standard Value

200 Ohms

Meter +ve Meter -ve

As shown in photo

Meter Range

0

Engine Temp ( C)

Resistance K Ohms

0

25 C

10.50 ± 7% KΩ

Measuring & Testing Equipment : Multimeter

Battery Charging Coil

Connections

Standard Value

200 Ohms

Meter +ve Meter -ve

Blue-White or Yellow Blue-White or Yellow

0.9 Ohms

SOP :

• Switch OFF engine.

• Disconnect stator plate coupler

• Connect multimeter between two Blue / White wires.

• Check resistance value between Blue / White & Blue / White.

Meter Range

Measuring & Testing Equipment : Multimeter

Pick-Up Coil Resistance

Connections

Standard Value

200 Ohms

Meter +ve Meter -ve

White / Red Black / Yellow

215 ± 20Ω

SOP :

• Switch Off Ignition Key.

• Disconnect Stator Plate Coupler

• Connect multimeter between White / Red & Black / Yellow wires.

• Measure resistance

Note: Ensure gap 0.5~0.7 mm between pole of pick-up coil & rotor

peep.

Meter Range

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Bajaj Auto International Business

5

Electricals

Electrical Checking Procedure

Measuring & Testing Equipment : Multimeter

Horn

Conditions

Standard Value

200 DC A

2.2 Ampere

SOP :

• Encircle clamp meter jaws around Brown wire of Horn.

• Press horn switch & check instantaneous current drawn by horn.

Meter Range

Encircle clamp meter jaws

around Brown wire of horn

H.T. Coils

Starter Relay

SOP :

• Switch OFF engine.

• Disconnect coupler from Relay.

• Connect multimeter to Starter Relay coil terminals.

• Check resistance.

Measuring & Testing Equipment : Test Jig or Multimeter

Connection : Test Jig - Connect starter relay coupler to Test Jig & it

show result as OK / Defective

200 Ohms

Meter Range

3.9 Ω ± 10%

Starter Relay

Coil Red -

Yellow Wire

Meter +ve

Connections

Starter

Relay Coil

Black Wire

Meter -ve

Standard Value

H.T. Coil : (Inspection Using Multimeter)

• Measure the primary winding resistance as follows

• Connect the multimeter between input terminal & GND plate on the core.

• Measure the secondary winding resistance as follows

• Remove the plug cap by turning it counter clockwise.

• Connect the multimeter between H.T. cable end & GND plate on the core.

• Measure primary winding & secondary winding resistance.

• If the value does not match as per, specifications 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 OK coil.

• Visually inspect the secondary winding lead.

• If it shows any damage, replace the coil.

Primary Winding

0

0.45±10%  at 25 C

Secondary Winding

0

5.0±10% K W at 25 C

Electricals

59

Bajaj Discover 125 UG Training Notes

Electrical Checking Procedure

Measuring & Testing Equipment : Multimeter

Battery Charging Voltage Measurement

Use fully charged battery while measuring

Connections

At 4500 RPM with

Heal Light ON

20 K Ohms

Meter +ve Meter -ve

Battery +ve Terminal Battery -ve Terminal

14.4 + 0.2 Volts

Meter Range

60

Bajaj Auto International Business

5

Electricals

Notes

Electricals

61

Bajaj Discover 125 UG Training Notes

Important SOP

Wind shield (Visor) Replacement

A

Foam strips

A

• Remove wind shield mounting

screws (Torque value : 0.14 –

0 . 1 6 K g . m ) w i t h p l a s t i c

washers using phillips head

screw driver & take out wind

shield.

• Ensure that 4 nos well nuts &

4 nos dampers shown in

photograph A are in good

condition. Replace them with

n e w o n e i f f o u n d c u t /

damaged.

Bulb Headlight Replacement

• Remove headlight assembly

mounting bracket –

- Bottom bolt with metal washer

using 8 mm spanner holding

nut with 10 mm spanner.

- Top side 2 nos. bolt with metal

washer using 10 mm spanner.

B

Foam strips

• Ensure that 3 nos foam strips

shown in photograph A & 1

nos foam strips as shown in

p h o t o g r a p h B a r e i n

good condition. Replace them

with new one if found cut /

damaged.

Note :- While refitment, ensure

the tightness of screws to

avoid rattling noise.

Well

nut

Damper

• Take out headlight assembly.

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Electricals

Important SOP

• Pull out dust cap.

• R e m o v e h e a d l i g h t b u l b

coupler.

• Press bulb holding clip as

shown by pink arrow & take

out clip as per blue arrow.

• Take out headlight bulb.

After fitment of all removed

parts, adjust headlight focus

as per SOP.

Flap Speedometer & Speedometer Assembly Replacement

• Take out headlight assembly.

• Remove wind shield (visor).

Also check dampers & foam

strips condition as explained in

wind shield replacement SOP.

• Remove headlight bulb.

• Pull out rubber bellow, remove

speedometer couplers & DRL

couplers.

• Remove speedo flap mounting

-

- Front side screw (1 nos) with

plastic washer using phillips

head screw driver.

- Top side screws (2 nos) with

plastic washer using phillips

head / Minus screw driver.

Electricals

Important SOP

63

Bajaj Discover 125 UG Training Notes

- LH & RH Side bolts (2 nos) with 10 mm spanner as shown

by blue arrows.

- Bottom side screws (2 nos) with metal washer using phillips

head / Minus screw driver as shown by blue circles.

- Take out flap speedometer along with speedometer assembly.

• Ensure that foam strip (2 nos)

on speedo flaps are in good

condition. Replace with new

one if found cut / damaged /

Permanent set

• Ensure that beading strips (4

nos) on speedo flaps are in

good condition. Replace with

n e w o n e i f f o u n d c u t /

damaged.

• R e m o v e s p e e d o m e t e r

mounting screws (4 nos.) with

metal washers using phillips

head screw driver & take out

speedometer assembly from

flap speedometer.

Note :- While refitment,

ensure the tightness of

screws & nut - bolts to

avoid rattling noise.

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Electricals

Important SOP

Headlight Fairing / Headlight with DRL / Headlight Mounting Bracket Replacement

RH

bracket

B

LH

bracket

• Remove flap speedometer

a l o n g w i t h s p e e d o m e t e r

assembly.

• Rem o ve h ead l igh t fai r ing

mounting screws (2 nos) with

metal washer using phillips

head screw driver.

• Take out headlight fairing.

• Ensure that foam strips (6

nos) on headlight are in good

condition. Replace with new

one if found cut / damaged /

permanent set.

• S e p a r a t e o u t Ta k e o u t

headlight assembly mounting

bracket & headlight assembly

with DRL.

• Take out collars (4 nos.) as

shown in photograph - A.

A

• Remove headlight mounting nuts (4 nos.) with metal washer

using 8 mm spanner.

Foam strips

• Ensure that grommets (6 nos) as shown

in photograph - B by pink arrow are in

good condition. Replace with new one if

found cut / damaged

• Re m ov e L H & RH Si d e b ra ck e t

mounting bolts (2 nos - each shown

by blue arrows in photograph-B) Torque

value : 0.31 - 0.42 Kg.m) using 10 mm

spanner & take out LH & RH side

bracket.

Electricals

Important SOP

65

Bajaj Discover 125 UG Training Notes

Central bracket

Top bracket

• Remove Top bracket pivot stud locking clip with plastic washer using

small screw driver as shown in photograph – C, D & E.

Ensure that grommets (2 nos) as shown in photograph - C & D are

in good condition. Replace with new one if found cut / damaged.

• Take out pivot studs & top bracket.

Note :- While refitment, ensure the tightness of screws & nut -

bolts to avoid rattling noise.

• Take out headlight assembly.

• Remove headlight assembly

mounting bracket –

- Bottom bolt with metal washer

using 8 mm spanner holding

nut with 10 mm spanner

- Top side 2 nos bolt with metal

washer using 10 mm spanner.

• Pull out dust cap.

• Remove headlight bulb coupler.

D

Grommet

Locking

clip

Pivot stud

C

Grommet

Locking clip

Pivot stud

Harness Headlight Replacement

E

Clip removal

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Bajaj Auto International Business

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Electricals

Important SOP

• R e m o v e D R L c o u p l e r s &

harness headlight coupler.

• Take out harness headlight.

Don’ts

Dos & Don’ts

Dos

• Adjust horn sound by

rotating the Phillips screw in

the direction of arrow

provided on horn.

• Never adjust the nut on horn cap side

and bracket end (horn back side) as it

will result in horn malfunctioning & failure.

• Do not remove silicon sealant from

adjustment screw as it will result in water

entry inside the horn.

Horn

• Replace spark plugs at

every 30,000 kms.

• Ensure that PVC cap on

magneto and CDI coupler

are intact.

• Grease used in CDI and

magneto coupler is in place.

• Do not replace spark plug by non

recommended type (different heat range).

• Do not remove grease from CDI and

magneto coupler as it is provided for rust

prevention.

Ignition System

• After washing the vehicle

ensure to apply dry air on

switches before operation.

• Ensure that grommets

provided on clutch switch,

front brake switch and rear

brake switch are intact.

• Do not apply direct pressurized water jet

on control switches.

• Do not lubricate electrical switches by oil

or grease.

• Do not over tighten the switch mounting

screw.

Switches

67

Bajaj Discover 125 UG Training Notes

Electricals

Electrical Circuit Diagrams

Battery Charging Circuit

CAPACITOR REGULATOR

INPUT

OUTPUT

GROUND

L/WL/W

W

B/Y

L/WL/W

W

10 A

W/B

W

FUSE

BOX

L/W

MAGNETO ASSEMBLY

BATTERY - 5Ah

+

-

W/B

L/W

B

L/W

B/Y

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Bajaj Auto International Business

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Electricals

Electrical Circuit Diagrams

Side Indicator Circuit

10 A

Br/L

Br

BATTERY - 5Ah

+

-

W/B

FRONT INDICATOR LAMP RH

12 V, 10 W

FRONT INDICATOR LAMP LH

12 V, 10 W

G

B/Y

IGNITION SWITCH

Br/L

W

SIDE INDICATOR SWITCH

(CONTROL SWITCH LH)

GOGr

L

OFF

R

GOGr

REAR INDICATOR LAMP RH

12 V, 10 W

B/Y

Gr

B/Y

Gr

REAR INDICATOR LAMP LH

12 V, 10 W

B/Y

G

DC FLASHER

Br

FUSE BOX

10A

W/B

W

Gr

B/Y

O

B/Y

G

W

Br

Gr

G

SPEEDOMETER

Gr

PIN 7

BATTERY (Before Ignition)

PIN 1

W

G

PIN 8

RIGHT TURN INDICATOR

LEFT TURN INDICATOR

PIN 11

GND

B/Y

PIN 20

SUPPLY (After Ignition)

Br

B

ON

OFF

G

B/Y

Gr

B/Y

Br

W

69

Bajaj Discover 125 UG Training Notes

Electricals

Electrical Circuit Diagrams

Horn Circuit

10 A

Br/L

Br

IGNITION SWITCH

Br/L

W

ON

OFF

Br

W

HORN

Br B/V

HORN SWITCH

(CONTROL SWITCH LH)

B/Y

B/V

B/Y

B

10 A

W/B

W

FUSE

BOX

BATTERY - 5Ah

+

-

W/B

B

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Bajaj Auto International Business

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Electricals

Electrical Circuit Diagrams

Starter Motor Circuit

PIN 9

PIN 1

PIN 11

PIN 20

BATTERY - 5Ah

+

-

W/B

IGNITION SWITCH

W

Br/L

STARTER RELAY

R

(CONTROL SWITCH RH)

M

STARTER MOTOR

R

Br/B

START

SWITCH

LG

NEUTRAL SWITCH

Y/G B/Y

LG

CLUTCH SWITCH

B

R/Y

Y/G R/Y

Y/G B/Y

LG

R

10A

W/B

W

FUSE BOX

R

Br

BATTERY (Before Ignition)

NEUTRAL

SPEEDOMETER

GND

W

LG

B/Y

W

Br

LG

R/Y

10 A

Br/L

Br

R/YBr/L

SUPPLY (After Ignition)

G/W

Br

W

B

ON

OFF

71

Bajaj Discover 125 UG Training Notes

Electricals

Electrical Circuit Diagrams

Brake Lamp Circuit

10A

W/B

W

FUSE BOX

BATTERY - 5Ah

+

-

W/B

10 A

Br/L

Br

B

IGNITION SWITCH

W

Br/L

ON

OFF

Br

W

FRONT BRAKE SWITCH

L Br

Br

REAR BRAKE SWITCH

L

Br L

BRAKE LAMP

L

B/Y

L

B/Y

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Bajaj Auto International Business

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Electricals

Electrical Circuit Diagrams

Lighting Circuit with DRL

10A

W/B

W

FUSE BOX

BATTERY - 5Ah

+

-

IGNITION SWITCH

Br/L

W

(CONTROL SWITCH LH)

HI

LO

HI / LO

SWITCH

PASS

SWITCH

Br R/Y V R/B

Y

R/Y

Y/L R/B

B/Y

Br

NUMBER PLATE LAMP

B/Y

Br

HEAD LAMP

WITH DRL

B/Y

V

Br

R/B

B/Y

R/Y

Br

V

R/B

B/Y

R/Y

10 A

Br/L

Br

ON

OFF

(CONTROL SWITCH RH)

Light Switch

Y/L

Br

V

Br

SPEEDOMETER

BATTERY (Before Ignition)

W

R/B

HIGH BEAM

GND

PIN 1

PIN 3

PIN 11

W

Br

B/Y

ILLUMINATION

PIN 13

SUPPLY (After Ignition) PIN 20

G/W

R

R/B

Br

V

B

Br

W

OFF

ON

TAIL LAMP

B/Y

Br

B/Y

Br

73

Bajaj Discover 125 UG Training Notes

Electricals

Electrical Circuit Diagrams

Fuel Meter Circuit

W

Br

SPEEDOMETER

W/Y

PIN 5

BATTERY (Before Ignition)

PIN 1

W

PIN 11

FUEL SENSOR

GND

B/Y

PIN 20

SUPPLY (After Ignition)

Br

IGNITION SWITCH

W

10A

W/B

W

FUSE BOX

Br/L

BATTERY - 5Ah

+

-

W/B

FUEL LEVEL SENSOR

10 A

Br/L

Br

W/Y

B/Y

W/Y B/Y

B

ON

OFF

Br

W

W/Y B/Y

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Bajaj Auto International Business

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Electricals

75

Bajaj Discover 125 UG Training Notes

Electrical Circuit Diagrams

Vehicle Speed Sensor Circuit

10A

W/B

W

FUSE BOX

BATTERY - 5Ah

+

-

IGNITION SWITCH

Br/L

W

10 A

Br/L

Br

SPEEDOMETER

BATTERY (Before Ignition)

W

L/W

SPEED SENSOR INPUT

GND

PIN 1

PIN 6

PIN 11

W

Br

B/Y

SPEED SENSOR SUPPLY

PIN 19

SUPPLY (After Ignition)

PIN 20

G/W

B

Br

W

OFF

ON

B/Y

VEHICLE SPEED SENSOR

L/W

R/W

B/Y

L/W

R/W

Br

Electricals

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Bajaj Auto International Business

5

Electricals

Electrical Circuit Diagrams

Ignition Circuit

ON

OFF

IGNITION SWITCH

Br/L

W

MAGNETO ASSEMBLY

COIL

PULSING

W/R B/Y

H.T. COIL 1

B/Y

B

LHS

SPARK

PLUG

H.T. COIL 2

B/YB/R

RHS

SPARK

PLUG

CDI

HT COIL O/P 2

HT COIL O/P 1

GROUND

BATTERY +VE

PULSER INPUT

THERMISTER INPUT

B/R

B

G/W

Br/L

W/R

B/W

ETS

10 A

W/B

W

FUSE

BOX

BATTERY - 5Ah

+

-

W/B

B

10 A

Br/L

Br

SPEEDOMETER

B

PIN 10

B

BATTERY (Before Ignition)

PIN 1

W

B/Y

PIN 11

G/W

RPM SIGNAL

GND

W

Br

PIN 20

SUPPLY (After Ignition)

Br

W

77

Bajaj Discover 125 UG Training Notes

Notes

Electricals

Bajaj Auto Limited

Akurdi Pune

411 035 India

T

el | +91 20 27472851

Fax | +91 20 27407385

www.bajajauto.com

CIN number

:

CIN

L65993PN2007PLC130076