2008

MOTORCYCLE

SERVICE MANUAL

Model : YW50X_

5PNF81972100 *5PNF81972100*

EAS00000

YW50X 2007

SUPPLEMENTARY SERVICE MANUAL

©2007 by Yamaha Motor Taiwan Co., Ltd.

First edition, June 2007

All rights reserved.

Any reproduction or unauthorized use

without the written permission of

Yamaha Motor Taiwan Co., Ltd.

is expressly prohibited.

Printed in CANADA

FORWORD

This supplementary service manual has been prepared to introduce new service and data for YW50BP

2001. For complete service manual procedures it is necessary to use this supplementary service

manual together with the following manual.

YW50BP 2001 SERVICE MANUAL : 5PN1-ME1

EAS00002

NOTICE

This manual was produced by the Yamaha Motor Taiwan Company, Ltd. primarily for use by Yamaha

dealers and their qualified mechanics. It is not possible to include all the knowledge of a mechanic in

one manual. Therefore, anyone who uses this book to perform maintenance and repairs on Yamaha

vehicles should have a basic understanding of mechanics and the techniques to repair these types

of vehicles. Repair and maintenance work attempted by anyone without this knowledge is likely to

render the vehicle unsafe and unfit for use.

Yamaha Motor Taiwan Company, Ltd. is continually striving to improve all of its models. Modifications

and significant changes in specifications or procedures will be forwarded to all authorized Yamaha

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

NOTE:

Designs and specifications are subject to change without notice.

EAS00005

IMPORTANT MANUAL INFORMATION

Particularly important information is distinguished in this manual by the following.

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 scooter operator, a bystander or a person checking or repairing the

scooter.

A CAUTION indicates special precautions that must be taken to avoid dam-

age to the scooter.

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

NOTE:

w

cC

Q

4-3

ENG

CYLINDER HEAD, CYLINDER AND PISTON

CYLINDER HEAD, CYLINDER AND PISTON

Job name/Part name

Cylinder head, Cylinder and piston

removal

Engine

Muffler/Gasket

Air shroud 2

Spark plug

Cylinder head/Cylinder head gasket

Cylinder

Piston pin clip

Piston pin/ Bearing

Piston

Piston ring set

Cylinder gasket

Remarks

Remove the parts in the order.

Refer to the “ENGINE REMOVAL” sec-

tion

Reverse the removal procedure for in-

stallation.

Order

1

2

3

4

5

6

7

8

9

10

Q’ty

1/1

1

1

1/1

1

2

1/1

1

1

1

4

5

6

7

10

1

2

3

26Nm(2.6 m.kg, 18.2 ft.lb)

T R

.

.

14Nm(1.4 m.kg, 10 ft.lb)

T R

.

.

9Nm(0.9 m.kg,6.5 ft.lb)

T R

.

.

New

New

New

E

8

9

CYLINDER HEAD, CYLINDER AND PISTON

4-4

ENG

PISTON PIN AND PISTON REMOVAL

1.

Remove:

8 Piston pin clip 1

NOTE:

Before removing the piston pin clip, cover the

crankcase with a clean rag so you will not acci-

dentally drop the clip into the crankcase.

2.

Remove:

8 Piston pin 1

8 Piston 2

8 Piston pin bearing 3

cC

Do not use a hammer to drive the piston pin

out.

CYLINDER HEAD INSPECTION

1.

Eliminate:

8 Carbon deposits

Use a rounded scrapper 1.

2.

Inspect:

8 Cylinder head warpage

Out of specification∅Re-surface.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Warpage measurement and re-surfacement

steps:

8 Attach a straight edge 1 and a thickness

gauge 2 on the cylinder head.

8 Measure the warpage limit.

Warpage limit:

0.03 mm(0.0012 in)

8 If the warpage is out of specification, reface

the cylinder head.

NOTE:

Rotate the head severai tires to avoid remov-

ing too much material from one side.

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

CYLINDER HEAD, CYLINDER, PISTON

2

1

EAS00007

HOW TO USE THIS MANUAL

This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive

explanations of all installation, removal, disassembly, assembly, repair and check procedures are

laid out with the individual steps in sequential order.

1 The manual is divided into chapters. An abbreviation and symbol in the upper right corner of

each page indicate the current chapter.

Refer to “SYMBOLS”.

2 Each chapter is divided into sections. The current section title is shown at the top of each page,

except in Chapter 3 (“PERIODIC CHECKS AND ADJUSTMENTS”), where the sub-section

title(s) appears.

3 Sub-section titles appear in smaller print than the section title.

4 To help identify parts and clarify procedure steps, there are exploded diagrams at the start of

each removal and disassembly section.

5 Numbers are given in the order of the jobs in the exploded diagram. A circled number indicates

a disassembly step.

6 Symbols indicate parts to be lubricated or replaced.

Refer to “SYMBOLS”.

7 A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of

parts, notes in jobs, etc.

8 Jobs requiring more information (such as special tools and technical data) are described se-

quentially.

8

4

5

7

1

3

2

6

GEN

INFO

SPEC

CHK

ADJ

ENG

TRBL

SHTG

CHAS

-

+

ELEC

4

M

B

LS

New

M

G

COOL

1

2

3

4

5

6

7

8

9

0

q

w

e

r

i

s

h

j

EAS00008

SYMBOLS

The following symbols are not relevant to every

vehicle.

Symbols 1 to 9 indicate the subject of each

chapter.

1 General information

2 Specifications

3 Periodic checks and adjustments

4 Chassis

5 Engine

6 Cooling system

7 Carburetor

8 Electrical system

9 Troubleshooting

Symbols 0 to u indicate the following.

0 Serviceable with engine mounted

q Filling fluid

w Lubricant

e Special tool

r Tightening torque

t Wear limit, clearance

y Engine speed

u Electrical data

Symbols i to g in the exploded diagrams indi-

cate the types of lubricants and lubrication

points.

i Engine oil

o Gear oil

p Molybdenum-disulfide oil

a Brake fluid

s Wheel-bearing grease

d Lithium-soap- based grease

f Molybdenum-disulfide grease

g Silicone grease

Symbols h to j in the exploded diagrams indi-

cate the following.

h Apply locking agent (LOCTITE^®)

j Replace the part

T R

.

.

t y u

LT

CARB

BF

o

p

a

S

d

f

g

EAS00010

TABLE OF CONTENTS

GENERAL INFORMATION

SPECIFICATIONS

PERIODIC CHECKS AND

ADJUSTMENTS

CARBURETOR

GEN

INFO

SPEC

CHK

ADJ

CARB

1

2

3

4

5

6

5

7

8

9

1-8

GEN

INFO

CHAPTER 1

GENERAL INFORMATION

SCOOTER IDENTIFICATION................................................................... 1-1

VEHICLE IDENTIFICATION NUMBER ............................................. 1-1

MODEL LABEL .................................................................................. 1-1

IMPORTANT INFORMATION................................................................... 1-2

PREPARATION FOR REMOVAL AND DISASSEMBLY ................... 1-2

REPLACEMENT PARTS ................................................................... 1-2

GASKETS, OIL SEALS AND O-RINGS............................................ 1-2

LOCK WASHERS/PLATES AND COTTER PINS............................. 1-3

BEARINGS AND OIL SEALS ............................................................ 1-3

CIRCLIPS ........................................................................................... 1-3

CHECKING THE CONNECTIONS ........................................................... 1-4

SPECIAL TOOLS ...................................................................................... 1-5

1-1

GEN

INFO

1

1

SCOOTER IDENTIFICATION

EAS00015

GENERAL INFORMATION

SCOOTER IDENTIFICATION

EAS00017

VEHICLE IDENTIFICATION NUMBER

The vehicle identification number 1 is stamped

into the frame.

EAS00018

MODEL LABEL

The model label 1 is affixed to the seat. This

information will be needed to order spare parts.

1-2

GEN

INFO

IMPORTANT INFORMATION

EAS00020

IMPORTANT INFORMATION

PREPARATION FOR REMOVAL AND DISAS-

SEMBLY

1. Before removal and disassembly, remove

all dirt, mud, dust and foreign material.

2. Use only the proper tools and cleaning

equipment.

Refer to the “SPECIAL TOOLS”.

3. When disassembling, always keep mated

parts together. This includes gears, cylin-

ders, pistons and other parts that have been

“mated” through normal wear. Mated parts

must always be reused or replaced as an

assembly.

4. During disassembly, clean all of the parts

and place them in trays in the order of dis-

assembly. This will speed up assembly and

allow for the correct installation of all parts.

5. Keep all parts away from any source of fire.

EAS00021

REPLACEMENT PARTS

Use only genuine Yamaha parts for all replace-

ments. Use oil and grease recommended by

Yamaha for all lubrication jobs. Other brands may

be similar in function and appearance, but infe-

rior in quality.

EAS00022

GASKETS, OIL SEALS AND O-RINGS

1. When overhauling the engine, replace all

gaskets, seals and O-rings. All gasket sur-

faces, oil seal lips and O-rings must be

cleaned.

2. During reassembly, properly oil all mating

parts and bearings and lubricate the oil seal

lips with grease.

1-3

GEN

INFO

IMPORTANT INFORMATION

EAS00023

LOCK WASHERS/PLATES AND COTTER

PINS

After removal, replace all lock washers/plates

1 and cotter pins. After the bolt or nut has been

tightened to specification, bend the lock tabs

along a flat of the bolt or nut.

EAS00024

BEARINGS AND OIL SEALS

Install bearings and oil seals so that the

manufacturer’s marks or numbers are visible.

When installing oil seals, lubricate the oil seal

lips with a light coat of lithium-soap-based

grease. Oil bearings liberally when installing, if

appropriate.

1 Oil seal

cC

Do not spin the bearing with compressed

air because this will damage the bearing

surfaces.

1 Bearing

EAS00025

CIRCLIPS

Before reassembly, check all circlips carefully

and replace damaged or distorted circlips. Al-

ways replace piston pin clips after one use. When

installing a circlip 1, make sure the sharp-edged

corner 2 is positioned opposite the thrust 3

that the circlip receives.

4 Shaft

1-4

GEN

INFO

CHECKING THE CONNECTIONS

EAS00026

CHECKING THE CONNECTIONS

Check the leads, couplers, and connectors for

stains, rust, moisture, etc.

1. Disconnect:

8lead

8coupler

8connector

2. Check:

8lead

8coupler

8connector

Moisture i Dry with an air blower.

Rust/stains i Connect and disconnect

several times.

3. Check:

8all connections

Loose connection i Connect properly.

NOTE:

If the pin 1 on the terminal is flattened, bend it

up.

4. Connect:

8lead

8coupler

8connector

NOTE:

Make sure all connections are tight.

5. Check:

8continuity

(with the pocket tester)

Pocket tester

90890-03112(YU-03112-C)

NOTE:

8 If there is no continuity, clean the terminals.

8 When checking the wire harness, perform

steps (1) to (3).

8 As a quick remedy, use a contact revitalizer

available at most part stores.

1-5

GEN

INFO

Tool NO.

Tool name / Function

Illustration

SPECIAL TOOLS

EAS00027

SPECIAL TOOLS

The following special tools are necessary for complete and accurate tune-up and assembly. Use

only the appropriate special tools as this will help prevent damage caused by the use of inappropri-

ate tools or improvised techniques. Special tools, part numbers or both may differ depending on the

country.

When placing an order, refer to the list provided below to avoid any mistakes.

NOTE:

8 For U.S.A. and Canada, use part number starting with “YM-”, “YU-”, or “ACC-”.

8 For others, use part number starting with “90890-”.

Rotor holding tool

This tool is used to hold the generator rotor

when removing or installing and generator

rotor bolt.

Clutch spring holder

These tool are used for removing the nut with

holding the compression spring.

Crankshaft installer set 1

Adapter 2

These tools are used to install the crank-

shaft.

Flywheel puller

This tool is used to remove the generator

rotor.

Crankcase separating tool

This tool is used to remove the crankshaft

or separate the crankcase.

Oil seal guide

This tool is used for protecting the oil seal

lip when installing the secondary sliding

sheave.

Steering nut wrench

This tool is used to loosen and tighten the

steering ring nut.

Sheave holder

This tool is used for holding the secondary

sheave.

90890-01235

YU-01235

90890-01337

YM-33285

YM-33285-6

90890-01284

YU-90050

90890-01383

YU-90062

90890-01189

YU-01189

90890-01135

YU-01135-B

90890-01384

YM-33299

90890-01403

YU-A9472

90890-01701

YS-01880-A

1

2

1-6

GEN

INFO

Tool NO.

Tool name / Function

Illustration

SPECIAL TOOLS

90890-06760

90890-03112

YU-03112-C

90890-01409

YM-01409

90890-01410

YM-01410

90890-06754

YM-34487

90890-85505

ACC-11001-05-01

90890-01348

YM-01348

90890-01268

YU-01268

90890-01367

YM-A9409-7

90890-01400

YM-A9409-3

90890-01326

YM-01326

90890-01294

YM-01300-1

Digital tachometer

This tool is needed for detecting engine rpm.

Pocket tester

This instrument is invaluable for checking

the electrical system.

Oil seal guide

This tool is used to install the left side crank-

case oil seal.

Oil seal installer

This tool is used to install the left side crank-

case oil seal.

Ignition checker

This tool is used to check the ignition sys-

tem components.

Yamaha bond NO.1215

Sealant (Quick Gasket ®)

This sealant (bond) is used on crankcase

mating surfaces (e.g., crankcase mating

surfaces).

Locknut wrench

This tool is used when removing or install-

ing the secondary sheave nut.

Ring nut wrench

This tool is used to loosen and tighten the

steering ring nut.

Fork seal driver weight 1

Fork seal driver attachment 2

These tools are used when installing the fork

seal.

T-handle 1

Damper rod holder 2

These tools are used to hold the damper rod

when removing or installing the damper rod.

1

2

1

2

41

46

1-7

GEN

INFO

Tool NO.

Tool name / Function

Illustration

SPECIAL TOOLS

90890-01312

YM-01312-A

Fuel level gauge

This gauge is used to measure the fuel le-

ver in the float chamber.

2-23

SPEC

CHAPTER 2

SPECIFICATIONS

GENERAL SPECIFICATIONS ................................................................. 2-1

ENGINE SPECIFICATIONS ..................................................................... 2-2

CHASSIS SPECIFICATIONS ................................................................... 2-6

ELECTRICAL SPECIFICATIONS ............................................................ 2-9

CONVERTION TABLE............................................................................ 2-12

GENERAL TIGHTENING TORQUE SPECIFICATIONS ....................... 2-12

TIGHTENING TORQUES........................................................................ 2-13

ENGINE............................................................................................ 2-13

CHASSIS.......................................................................................... 2-14

LUBRICATION POINTS AND LUBRICANT TYPES............................. 2-16

ENGINE............................................................................................ 2-16

CHASSIS.......................................................................................... 2-17

CABLE ROUTING .................................................................................. 2-18