Yamaha YZ85W1 User manual

2007
YZ85W1
5PA-28197-E0
SERVICE MANUAL
YZ85(W)
YZ85LW(W)

YZ85W1/YZ85 (W)/YZ85LW (W)
SERVICE MANUAL
©2006 by Yamaha Motor Co., Ltd.
First edition, April 2006
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.
N
O
TE:
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 dam-
age 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.
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”.
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.
Sub-section titles appear in smaller print than the section title.
To help identify parts and clarify procedure steps, there are exploded diagrams at the start of
each removal and disassembly section.
Numbers are given in the order of the jobs in the exploded diagram. A circled number indicates a
disassembly step.
Symbols indicate parts to be lubricated or replaced.
Refer to “SYMBOLS”.
A job instruction chart accompanies the exploded diagram, providing the order of jobs, names of
parts, notes in jobs, etc.
Jobs 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 to indicate the subject of each
chapter.
General information
Specifications
Periodic checks and adjustments
Chassis
Engine
Cooling system
Carburetor(s)
Electrical system
Tuning
Troubleshooting
Symbols to indicate the following.
Serviceable with engine mounted
Filling fluid
Lubricant
Special tool
Tightening torque
Wear limit, clearance
Engine speed
Electrical data
Symbols to in the exploded diagrams
indicate the types of lubricants and lubrication
points.
Engine oil
Gear oil
Molybdenum-disulfide oil
Wheel-bearing grease
Lithium-soap- based grease
Molybdenum-disulfide grease
Symbols to in the exploded diagrams
indicate the following.
Apply locking agent (LOCTITE®)
Replace the part with a new one.

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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
COOLING SYSTEM COOL 6
CARBURETOR CARB 7
ELECTRICAL SYSTEM ELEC 8
TUNING TUN 9
TROUBLESHOOTING TRBL
SHTG 10

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
FUEL AND ENGINE MIXING OIL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
CHECKING THE CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
SPECIAL TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

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

GEN
INFO
1-2
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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 replace-
ments. Use oil and grease recommended 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.
lip
oil
lip
spring
grease
IMPORTANT INFORMATION

GEN
INFO
1-3
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LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace all lock washers/plates
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.
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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.
Oil seal
CAUTION:
Do not spin the bearing with compressed
air because this will damage the bearing
surfaces.
Bearing
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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 , make sure the
sharp-edged corner is positioned opposite
the thrust that the circlip receives.
Shaft
IMPORTANT INFORMATION