Yamaha YBR125ED 2005 User manual

2005
YBR125ED
3D9-F8197-E0
SERVICE MANUAL

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YBR125ED 2005
SERVICE MANUAL
©2005 by Yamaha Motor Co., Ltd.
First edition, January 2005
All rights reserved.
Any reproduction or unauthorized use
without the written permission of
Yamaha Motor Co., Ltd.
is expressly prohibited.

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NOTICE
This manual was produced by the Yamaha Motor Company, Ltd. primarily for use by Yamaha deal-
ers 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 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 deal-
ers and will appear in future editions of this manual where applicable.
NOTE:
_
Designs and specifications are subject to change without notice.
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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 vehicle operator, a bystander or a person checking or repairing the vehicle.
A CAUTION indicates special precautions that must be taken to avoid damage
to the vehicle.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
NOTE:

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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.
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”.
2Each 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.
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.
Refer to “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.

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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
4Chassis
5Engine
6Carburetor
7Electrical system
8Troubleshooting
Symbols 9to Findicate the following.
9Serviceable with engine mounted
0Filling fluid
ALubricant
BSpecial tool
CTightening torque
DWear limit, clearance
EEngine speed
FElectrical data
Symbols Gto Lin the exploded diagrams
indicate the types of lubricants and lubrication
points.
GEngine oil
HGear oil
IMolybdenum-disulfide oil
JWheel-bearing grease
KLithium-soap-based grease
LMolybdenum-disulfide grease
Symbols Mto Nin the exploded diagrams
indicate the following.
MApply locking agent (LOCTITE®)
NReplace the part
12
34
56
78
90
AB
CD
EF
GHI
JKL
MN
GEN
INFO
SPEC
CHK
ADJ
CHAS
ENG
CARB
–+
ELEC TRBL
SHTG
T
R
.
.
EGM
BLS M
LT
New

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TABLE OF CONTENTS
GENERAL INFORMATION GEN
INFO 1
SPECIFICATIONS SPEC 2
PERIODIC CHECKS AND
ADJUSTMENTS CHK
ADJ 3
CHASSIS CHAS 4
ENGINE ENG 5
CARBURETOR CARB 6
ELECTRICAL SYSTEM ELEC 7
TROUBLESHOOTING TRBL
SHTG 8
–+

GEN
INFO
CHAPTER 1
GENERAL INFORMATION
VEHICLE 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
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GENERAL INFORMATION
VEHICLE IDENTIFICATION
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VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1is
stamped into the right side of the steering head
pipe.
1
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MODEL LABEL
The model label 1is affixed to the frame. This
information will be needed to order spare
parts.
1
VEHICLE IDENTIFICATION

1 - 2
GEN
INFO
IMPORTANT INFORMATION
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IMPORTANT INFORMATION
PREPARATION FOR REMOVAL AND
DISASSEMBLY
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.
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REPLACEMENT PARTS
Use only genuine Yamaha parts for all
replacements. Use oil and grease recom-
mended by Yamaha for all lubrication jobs.
Other brands may be similar in function and
appearance, but inferior in quality.
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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
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LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace all lock washers/plates
1and cotter pins. After the bolt or nut has
been tightened to specification, bend the lock
tabs along a flat of the bolt or nut.
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BEARINGS AND OIL SEALS
Install bearings and oil seals so that the manu-
facturer’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 appro-
priate.
1Oil seal
CAUTION:
_
Do not spin the bearing with compressed
air because this will damage the bearing
surfaces.
1Bearing
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CIRCLIPS
Before reassembly, check all circlips carefully
and replace damaged or distorted circlips.
Always replace piston pin clips after one use.
When installing a circlip 1, make sure the
sharp-edged corner 2is positioned opposite
the thrust 3that the circlip receives.
4Shaft