E

FOREWORD

This Supplementary Service Manual has been prepared to introduce new service and data for the

VMX12 ’93. For complete service information procedures it is necessary to use this Supplementary

Service Manual together with the following manual.

VMX12 ’86 SERVICE MANUAL: 2EN-ME1

VMX12 ’91 SUPPLEMENTARY SERVICE MANUAL: 2EN-AE1

VMX12 ’93

SUPPLEMENTARY

SERVICE MANUAL

1992 by Yamaha Motor Co., Ltd.

1st Edition, November 1992

All rights reserved.

Any reprinting or unauthorized use

without the written permission of

Yamaha Motor Co., Ltd.

is expressly prohibited.

E

CAUTION:

NOTICE

This manual was written by Yamaha Motor Company Ltd. primarily for use by Yamaha dealers and

qualified mechanics. It is not possible to put an entire mechanic’s education into one manual, so per-

sons using this book to perform maintenance and repairs on Yamaha motorcycles should have a basic

understanding of the mechanical concepts and procedures inherent in motorcycle repair technology.

Without such knowledge, attempted repairs or service to the motorcycle may render it unfit to use

and/or unsafe.

Yamaha Motor Company Ltd. is continually striving to improve all models manufactured by Yamaha.

Modifications and significant changes in specifications or procedures will be forwarded to all Autho-

rized Yamaha dealers and will, where applicable, appear in future editions of this manual.

PARTICULARLY IMPORTANT INFORMATION

This material is distinguished by the following notation.

The Safety Alert Symbol means ATTENTION! BECOME ALERT! YOUR

SAFETY IS INVOLVED!

Failure to follow WARNING instructions could result in severe injury or death to

the motorcycle operator, a bystander, or a person inspecting or repairing the

motorcycle.

A CAUTION indicates special precautions that must be taken to avoid damage

to the motorcycle.

NOTE:

A NOTE provides key information to make procedures easier or clearer.

E

HOW TO USE THIS MANUAL

CONSTRUCTION OF THIS MANUAL

This manual consists of chapters for the main categories of subjects. (See “Illustrated symbols”)

1st title 1 :

This is a chapter with its symbol on the upper right of each page.

2nd title 2 :

This title appears on the upper of each page on the left of the chapter symbol.

(For the chapter “Periodic inspection and adjustment” the 3rd title appears.)

3rd title 3 :

This is a final title.

MANUAL FORMAT

All of the procedures in this manual are organized in a sequential, step-by-step format. The information

has been compiled to povide the mechanic with an easy to read, handy reference that contains com-

prehensive explanations of all disassembly, repair, assembly, and inspections.

A set of particularly important procedure 4 is placed between a line of asterisks “

” with each proce-

dure preceded by “
”.

IMPORTANT FEATURES

Data and a special tool are framed in a box preceded by a relevant symbol 5 .

An encircled numeral 6 indicates a part name, and an encircled alphabetical letter data or an align-

ment mark 7 , the others being indicated by an alphabetical letter in a box 8 .

A condition of a faulty component will precede an arrow symbol and the course of action required the

symbol 9 .

EXPLODED DIAGRAM

Each chapter provides exploded diagrams before each disassembly section for ease in identifying cor-

rect disassembly and assembly procedures.

E

21

1

3

5

7

9

2

4

8

6

23

22

20

18

19

17

15

14

13

11

12

10

GEN

INFO

SPEC

ENG

CARB

ELEC

CHAS

COOL

INSP

ADJ

TRBL

SHTG

16

24

ILLUSTRATED SYMBOLS

(Refer to the illustration)

Illustrated symbols 1 to 9 are designed as

thumb tabs to indicate the chapter’s number

and content.

1 General information

2 Specifications

3 Periodic inspection and adjustment

4 Engine

5 Cooling system

6 Carburetion

7 Chassis

8 Electrical

9 Troubleshooting

Illustrated symbols ¹⁰ to ¹⁶ are used to identify

the specifications appearing in the text.

10 Filling fluid

11 Lubricant

12 Special tool

13 Tightening

14 Wear limit, clearance

15 Engine speed

16 Ω, V, A

Illustrated symbols ¹⁷ to ²⁴ in the exploded dia-

gram indicate grade of lubricant and location of

lubrication point.

17 Apply engine oil

18 Apply gear oil

19 Apply molybdenum disufide oil

20 Apply wheel bearing grease

21 Apply lightweight lithium-soap base grease

22 Apply molybdenum disulfide grease

23 Apply locking agent (LOCTITE^)

24 Use new one

E

CONTENTS

GENERAL INFORMATION

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MOTORCYCLE IDENTIFICATION

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . .

VEHICLE IDENTIFICATION NUMBER (For E)

1

. . . . . . . . . . . . . . .

FRAME SERIAL NUMBER (Except for E)

1

. . . . . . . . . . . . . . . . . . .

ENGINE SERIAL NUMBER

1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SPECIAL TOOL

2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FOR CHASSIS SERVICE

2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SPECIFICATIONS

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL SPECIFICATIONS

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MAINTENANCE SPECIFICATIONS

4

. . . . . . . . . . . . . . . . . . . . . . . . . . .

ENGINE

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ELECTRICAL

5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CHASSIS

6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FRONT AND REAR BRAKE

6

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FRONT FORK

7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

REMOVAL

8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DISASSEMBLY

9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INSPECTION

10

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ASSEMBLY

11

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INSTALLATION

14

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

E

–1–

E

MOTORCYCLE IDENTIFICATION

GEN

INFO

NOTE:

NOTE:

NOTE:

GENERAL

INFORMATION

MOTORCYCLE IDENTIFICATION

VEHICLE IDENTIFICATION NUMBER (For E)

The vehicle identification number 1 is stamped

into the steering head pipe.

Starting serial number:

JYA2ENS0-PA041101

The vehicle identification number is used to

identify your motorcycle and may be used to

register your motorcycle with the licensing au-

thority in your state.

FRAME SERIAL NUMBER

(Except for E)

The frame serial number 1 is stamped into the

right side of steering head.

Starting serial number:

2EN-031101 (F) (I) (B) (PRT) (GB)

The first three digits of these numbers are for

model identifications; the remaining digits are

the unit production number.

ENGINE SERIAL NUMBER

The engine serial number 1 is stamped into the

left side of the engine.

Starting serial number:

2EN-031101 (F) (I) (B) (PRT) (GB)

2EN-041101 (E)

The first three digits of these numbers are for

model identifications; the remaining digits are

the unit production number.

Designs and specifications are subject to

change without notice.

–2–

E

SPECIAL TOOLS

GEN

INFO

Refer to the list provided to avoid errors when

placing an order.

P/N. YM-




, YU-




For USA,

YS-




, YK-




Califo-

mia,

ACC-

CDN

P/N. 90890-

For EUR,

AUS

1

1

2

T-Handle

P/N. YM-01326

P/N. 90890-01326

For damper rod

holder (29 mm)

P/N. YM-33962

P/N. 90890-01375

These tools are used to loosen and tighten

the front fork damper rod holding bolt.

Front fork seal driver

(weight)

P/N. YM-33963

P/N. 90890-01367

Adapter (43 mm)

P/N. YM-8020

P/N. 90890-01374

These tools are used when installing the

fork seal:

2

1

2

SPECIAL TOOLS

The proper special tools are necessary for com-

plete and accurate tune-up and assembly. Us-

ing the correct special tool will help prevent

damage caused by the use of improper tools or

improvised techniques.

The shape and part number used for the special

tool differ by country, so two types are provided.

FOR CHASSIS SERVICE

–3–

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GENERAL SPECIFICATIONS

SPEC

SPECIFICATIONS

GENERAL SPECIFICATIONS

Model

VMX12

Model code number:

Engine starting number:

Frame starting number:

Vehicle identification number:

3LR8 (F) (I) (B) (PRT) (GB)

3LR9 (E)

2EN-031101 (F) (I) (B) (PRT) (GB)

2EN-041101 (E)

2EN-031101 (F) (I) (B) (PRT) (GB)

JYA2ENS0 PA041101 (E)

Minimum turning radius:

2,900 mm (114 in)

Tire:

Type

Size (F)

Size (R)

Wear limit

Tubeless

110/90V 18

METZELER/ME33

150/90VB 15 M/C

METZELER/ML2

1.0 mm (0.04 in)

–4–

E

MAINTENANCE SPECIFICATIONS

SPEC

MAINTENANCE SPECIFICATIONS

ENGINE

Model

VMX12

Carburetor:

I.D. Mark

Main jet

(M.J.)

Main air jet

(M.A.J.)

Jet needle

(J.N.)

Needle jet

(N.J.)

Pilot jet

(P.J.)

Pilot air jet

(P.A.J.1)

Pilot screw

(P.S.)

Pilot outlet

(P.O.)

Bypass 1

(B.P.1)

Bypass 2

(B.P.2)

Bypass 3

(B.P.3)

Valve seat size

(V.S.)

Starter jet

(G.S.1)

Starter jet

(G.S.2)

Fuel level

(F.L.)

Engine idling speed

Vacuum pressure at idling speed

3LR-01

#150

ø2.0

5DZ19-3

Y-0

#42.5

#95

2 and 1/2 turn out

0.9

0.8

0.8

0.9

1.5

#45

#0.8

15  17 mm (0.59  0.66 in)

950  1,050 r/min

200 mm Hg (7.87 in Hg)

CHASSIS

Model

VMX12

Front suspension:

Front fork travel

Fork spring free length

<Limit>

Collar length

Spring rate:

K1

K2

Stroke

K1

K2

Optional spring

Oil capacity

Oil level

Oil grade

Enclosed air pressure (standard)

<Min.  Max.>

140 mm (5.51 in)

386.5 mm (15.2 in)

<381.5 mm (15.0 in)>

245 mm (9.65 in)

3.75 N/mm (0.375 kg/mm, 21.0 lb/in)

4.90 N/mm (0.5 kg/mm, 28.0 lb/in)

0  78 mm (0  3.07 in)

78  140 mm (3.07  5.51 in)

No.

619 cm³ (21.8 lmp oz, 20.9 US oz)

123 mm (4.8 in)

Yamaha fork oil 10wt or equivalent

39.2 kPa (0.4 kg/cm², 5.7 psi)

<39.2  98.1 kPa (0.4  1.0 kg/cm², 5.7  14.2 psi)>

Front disc brake:

Type

Disc outside diameter
thickness

Pad thickness

Inner

<Limit>

Pad thickness

Outer

<Limit>

Dual

298
5.0 mm (11.7
0.20 in)

5.0 mm (0.20 in)

<0.5 mm (0.02 in)>

5.0 mm (0.20 in)

<0.5 mm (0.02 in)>

Master cylinder inside diameter

Caliper cylinder inside diameter

Brake fluid type

15.87 mm (0.63 in)

33.96 + 30.23 mm (1.33 + 1.19 in)

DOT #4 or DOT #3

–5–

E

MAINTENANCE SPECIFICATIONS

SPEC

ELECTRICAL

Model

VMX12

T.C.I.:

Pickup coil resistance (color)

T.C.I. Unit-model/Manufacturer

81
121 Ω at 20
C (68
F) (Black – Orange)

BB7224/HITACHI

–6–

E

FRONT AND REAR BRAKE

CHAS

1 Air bleed screw

2 Retaining pin

3 Dust seal

4 Piston seal

5 Piston

6 Brake pad

7 Pad spring

8 Caliper assembly

9 Brake disc

E The arrow mark on the pad

spring must point in the disc ro-

tating direction.

A

FRONT CALIPER

B

PAD WEAR LIMIT:

0.5 mm (0.02 in)

C

D

MINIMUM DISC THICKNESS:

4.5 mm (0.18 in)

MAXIMUM DEFLECTION:

0.3 mm (0.01 in)

35 Nm (3.5 m
kg, 25 ft
lb)

20 Nm (2.0 m
kg, 14 ft
lb)

20 Nm (2.0 m
kg, 14 ft
lb)

35 Nm (3.5 m
kg, 25 ft
lb)

E

PAD SPRING

5 Nm (0.5 m
kg, 3.6 ft
lb)

CHASSIS

FRONT AND REAR BRAKE

–7–

E

FRONT FORK

CHAS

1 Front fork assembly

2 Inner fork tube

3 Piston metal

4 Dust cover

5 Retaining clip

6 Oil seal

7 Seal spacer

8 Slide metal

23 Nm (2.3 m
kg, 17 ft
lb)

A

FORK OIL (EACH):

B

CAPACITY:

619 cm³ (21.8 lmp oz, 20.9 US oz)

C

GRADE:

Yamaha Fork Oil 10wt or equivalent

D

STD. AIR PRESSURE:

39.2 kPa (0.4 kg/cm², 5.7 psi)

E

MIN. TO MAX. AIR PRESSURE:

39.2
98.1 kPa

(0.4
1.0 kg/cm², 5.7
14.2 psi)

F

FORK SPRING FREE

LENGTH (LIMIT):

381.5 mm (15.0 in)

20 Nm (2.0 m
kg, 14 ft
lb)

23 Nm (2.3 m
kg, 17 ft
lb)

62 Nm (6.2 m
kg, 45 ft
lb)

FRONT FORK

9 Outer fork tube

10 Oil lock piece

11 Damper rod

12 Fork spring

13 Spring seat

14 Collar

15 Cap bolt

16 Fork cap