Yamaha TW125 2003 Manual

FOREWORD
This Supplementary Service Manual has been prepared to introduce new service and data for the
TW125 2003. For complete service information procedures it is necessary to use this Supplementary
Service Manual together with the following manual.
TW125 SERVICE MANUAL: 5EK1-AE1
TW125 SUPPLEMENTARY SERVICE MANUAL : 5EK1-AE2
TW125 2003
SUPPLEMENTARY
SERVICE MANUAL
!2002 by Yamaha Motor Co., Ltd.
First Edition, October 2002
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd. is expressly
prohibited.

NOTE:
WARNING
CAUTION:
EB001000
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
motorcycle 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.
Yamaha Motor Company, Ltd. is continually striving to improve all 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.
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!
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.

1
2
5
7
6
43
8
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 inspection procedures are
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.
(In Chapter 3, “Periodic Inspections and Adjustments”, the sub-section title appears at the top of 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 8indicate the subject of each
chapter.
1General information
2Specifications
3Periodic checks 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 in the exploded diagrams indi-
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 in the exploded diagrams indi-
cate the following:
23 Apply locking agent (LOCTITE")
24 Replace the part

CONTENTS
SPECIFICATIONS
GENERAL SPECIFICATIONS 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CHASSIS SPECIFICATIONS 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ELECTRICAL SPECIFICATIONS 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CABLE ROUTING 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ELECTRICAL
CHECKING THE SWITCHES 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
LIGHTING SYSTEM 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
CIRCUIT DIAGRAM 14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TROUBLESHOOTING
FAULTY LIGHTING SYSTEM 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
HEADLIGHT DOES NOT COME ON 17. . . . . . . . . . . . . . . . . . . . . . . . . .
HEADLIGHT BULB BURNT OUT 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TW125 2003 WIRING DIAGRAM

–1–
GENERAL SPECIFICATIONS/CHASSIS SPECIFICATIONS SPEC
SPECIFICATIONS
GENERAL SPECIFICATIONS
Item Standard Limit
Model code 5RS3, 5RS4 !!!
CHASSIS SPECIFICATIONS
Item Standard Limit
Frame
Frame type
Caster angle
Trail
Diamond
25"83’
93 mm
!!!
!!!
!!!
Tire pressure (cold tire)
Maximum load-except motorcycle
Loading condition A*
front
rear
Loading condition B*
front
rear
Off road riding
front
rear
High speed riding
front
rear
180 kg
0 !90 kg
150 kPa (1.5 kg/cm2, 1.5 bar)
150 kPa (1.5 kg/cm2, 1.5 bar)
90 !180 kg
150 kPa (1.5 kg/cm2, 1.5 bar)
175 kPa (1.75 kg/cm2, 1.75 bar)
125 kPa (1.25 kg/cm2, 1.25 bar)
125 kPa (1.25 kg/cm2, 1.25 bar)
150 kPa (1.5 kg/cm2, 1.5 bar)
175 kPa (1.75 kg/cm2, 1.75 bar)
!!!
!!!
!!!
!!!
!!!
!!!
!!!
!!!
!!!
!!!
!!!
*Load is the total weight of cargo, rider, passenger, and accessories.

–2–
CHASSIS SPECIFICATIONS/
ELECTRICAL SPECIFICATIONS SPEC
Item Standard Limit
Front suspension
Front fork travel
Fork spring free length
Fitting length
Spring rate (K1)
Stroke (K1)
Oil capacity
Oil level
Oil grade
Inner tube vend limit
150 mm
330.4 mm
325.4 mm
4.9 N/mm (0.5 kg/mm)
0 !150 mm
0.259 L (259 cm3)
122 mm
Fork oil 10 WT or equivalent
!!!
!!!
324 mm
!!!
!!!
!!!
!!!
!!!
!!!
0.2 mm
Rear suspension
Shock absorber stroke
Spring free length
Fitting length
Spring rate (K1)
(K2)
Stroke (K1)
(K2)
48 mm
190 mm
185 mm
127.5 N/mm (12.8 kg/mm)
186.4 N/mm (18.6 kg/mm)
0 !32 mm
32 !48 mm
!!!
173 mm
!!!
!!!
!!!
!!!
!!!
Drive chain
Type/manufacturer
No. of links
Chain free play
428HD/DAIDO
126
35 !60 mm
!!!
!!!
!!!
Rear brake
Type
Drum inside diameter
Shoe thickness
Shoe spring free length
Leading, trailing
130 mm
4 mm
52 mm
!!!
131 mm
2 mm
!!!
ELECTRICAL SPECIFICATIONS
Item Standard Limit
C.D.I.
Pickup coil resistance/color
Source coil resistance/color
C.D.I. unit model/manufacturer
656 !984 Ωat 20"C/
Red – White
624 !936 Ωat 20"C/
Brown – Green
5BT/YAMAHA
!!!
!!!
!!!
Headlight relay
Model/manufacturer
Coil resistance
G8MS-1A48T-L2-F28 /OMRON
90 !110 Ω
!!!
!!!