Yamaha TW125 1999 User manual

EAS00000
TW125
SERVICE MANUAL
1998 by Yamaha Motor Co., Ltd.
1st Edition, July 1998
All rights reserved. Any reprinting or
unauthorized use without the written
permission of Yamaha Motor Co., Ltd.
is expressly prohibited.

NOTE:
WARNING
CAUTION:
EAS00002 NOTICE
This manual was produced by the Yamaha Motor Company 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,
so it is assumed that anyone who uses this book to perform maintenance and repairs on Yamaha mo-
torcycle has a basic understanding of the mechanical ideas and the procedures of motorcycle repair.
Repairs attempted by anyone without this knowledge are likely to render the motorcycle unsafe and
unfit for use.
YamahaMotorCompany,Ltd.,iscontinuallystrivingtoimproveallitsmodels.Modificationsandsignif-
icant changes in specifications or procedures will be forwarded to all authorized Yamaha dealers and
will appear in future editions of this manual where applicable.
Designs and specifications are subject to change without notice.
EAS00004
IMPORTANT INFORMATION
Particularly important information is distinguished in this manual by the following notations.
The Safety Alert Symbol means ATTENTION! BECOME ALERT!
YOUR SAFETY IS INVOLVED!
FailuretofollowWARNINGinstructionscouldresultinsevereinjuryor
deathtothemotorcycleoperator,abystanderorapersoninspectingor
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.

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EAS00007 HOW TO USE THIS MANUAL
This manual is intended as a handy, easy-to-read reference book for the mechanic. Comprehensive
explanationsofallinstallation,removal,disassembly,assembly, repair and inspection proceduresare
laid out with the individual steps in sequential order.
1The manual is divided into chapters. An abbreviation and symbol in the upper right corner of each
page indicate the current chapter. Refer to “SYMBOLS” on the following page.
2Each chapter is divided into sections. The current section title is shown at the top of each page,
except in Chapter 3 (“Periodic Inspections and Adjustments”), where the sub-section title(-s) appear.
(InChapter 3, “Periodic Inspections and Adjustments”, the sub-section title appears atthe topof each
page, instead of the section title.)
3Sub-section titles appear in smaller print than the section title.
4To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section.
5Numbers are given in the order of the jobs in the exploded diagram. A circled number indicates a
disassembly step.
6Symbols indicate parts to be lubricated or replaced (see “SYMBOLS”).
7A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
8Jobs requiring more information (such as special tools and technical data) are described sequen-
tially.

21
1
3
5
7
9
2
4
8
6
23 24
2220
18 1917
15
1413
11 12
10
GEN
INFO SPEC
ENG
CARB
ELEC
CHAS
CHK
ADJ
TRBL
SHTG
16
EAS00009
SYMBOLS
The following symbols are not relevant to every
vehicle.
Symbols 1to 9indicate the subject of each
chapter.
1General information
2Specifications
3Periodic inspections and adjustments
4Engine
5Carburetor(-s)
6Chassis
7Electrical system
8Troubleshooting
Symbols 9to 16 indicate the following.
9Serviceable with engine mounted
10 Filling fluid
11 Lubricant
12 Special tool
13 Tightening torque
14 Wear limit, clearance
15 Engine speed
16 Electrical data
Symbols 17 to 22 intheexplodeddiagramsindi-
cate the types of lubricants and lubrication
points.
17 Engine oil
18 Gear oil
19 Molybdenum disulfide oil
20 Wheel bearing grease
21 Lithium soap base grease
22 Molybdenum disulfide grease
Symbols 23 to 24 intheexplodeddiagramsindi-
cate the following:
23 Apply locking agent (LOCTITE)
24 Replace the part

GENERAL INFORMATION
SPECIFICATIONS
PERIODIC INSPECTION AND
ADJUSTMENT
ENGINE OVERHAUL
CARBURATION
CHASSIS
ELECTRICAL
TROUBLESHOOTING
GEN
INFO 1
SPEC 2
3
ENG 4
CARB 5
CHAS 6
ELEC 7
TRBL
SHTG 8
CHK
ADJ
INDEX

GEN
INFO
1

CHAPTER 1.
GENERAL INFORMATION
MOTORCYCLE IDENTIFICATION 1–1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VEHICLE IDENTIFICATION NUMBER 1–1. . . . . . . . . . . . . . . . . . . . . . . . .
MODEL CODE 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. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .