Yamaha XT660R User manual

2004
XT660R(S)
XT660X(S)
5VK1-AE1
SERVICE MANUAL

EAS00000
XT660R(S)/XT660X(S) 2004
SERVICE MANUAL
©2003 by MBK Industrie
First edition, December 2003
All rights reserved.
Any reproduction or unauthorized use
without the written permission of
MBK Industrie
is expressly prohibited.

EAS00002
NOTICE
This manual was produced by MBK Industrie primarily for use by Yamaha dealers and their quali-
fied mechanics. It is not possible to include all the knowledge of a mechanic in one manual. There-
fore, 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 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.
NOTE:
_
Designs and specifications are subject to change without notice.
EAS00004
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 motorcycle operator, a bystander or a person checking or repairing
the motorcycle.
A CAUTION indicates special precautions that must be taken to avoid dam-
age to the motorcycle.
A NOTE provides key information to make procedures easier or clearer.
WARNING
CAUTION:
NOTE:

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.
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.

EAS00008
SYMBOLS
The following symbols are not relevant to
every vehicle.
Symbols 1to 9indicate the subject of each
chapter.
1General information
2Specifications
3Periodic checks and adjustments
4Chassis
5Engine
6Cooling system
7Fuel injection system
8Electrical system
9Troubleshooting
Symbols 0to Gindicate the following.
0Serviceable with engine mounted
AFilling fluid
BLubricant
CSpecial tool
DTightening torque
EWear limit, clearance
FEngine speed
GElectrical data
Symbols Hto Min the exploded diagrams
indicate the types of lubricants and lubrication
points.
HEngine oil
IGear oil
JMolybdenum-disulfide oil
KWheel-bearing grease
LLithium-soap-based grease
MMolybdenum-disulfide grease
Symbols Nto Oin the exploded diagrams
indicate the following.
NApply locking agent (LOCTITE®)
OReplace the part
12
34
56
78
90
AB
CD
EFG
HIJ
KLM
NO
GEN
INFO
SPEC
CHK
ADJ
CHAS
ENG
COOL
FI –+
ELEC
TRBL
SHTG
T
R
.
.
EGM
BLS M
LT
New

EAS00010
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
FUEL INJECTION SYSTEM FI 7
ELECTRICAL SYSTEM ELEC 8
TROUBLESHOOTING TRBL
SHTG 9
–+

GEN
INFO 1

GEN
INFO
CHAPTER 1
GENERAL INFORMATION
MOTORCYCLE IDENTIFICATION..................................................................1-1
VEHICLE IDENTIFICATION NUMBER .....................................................1-1
MODEL LABEL..........................................................................................1-1
FEATURES......................................................................................................1-2
OUTLINE ...................................................................................................1-2
FI SYSTEM................................................................................................1-3
IMPORTANT INFORMATION .........................................................................1-4
PREPARATION FOR REMOVAL AND DISASSEMBLY...........................1-4
REPLACEMENT PARTS...........................................................................1-4
GASKETS, OIL SEALS AND O-RINGS ....................................................1-4
LOCK WASHERS/PLATES AND COTTER PINS .....................................1-5
BEARINGS AND OIL SEALS ....................................................................1-5
CIRCLIPS ..................................................................................................1-5
CHECKING THE CONNECTIONS ..................................................................1-6
SPECIAL TOOLS ............................................................................................1-7

GEN
INFO

1 - 1
GEN
INFO
EAS00014
GENERAL INFORMATION
MOTORCYCLE IDENTIFICATION
EAS00017
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1is
stamped into the right side of the steering head
pipe.
EAS00018
MODEL LABEL
The model label 1is affixed to the frame. This
information will be needed to order spare
parts.
MOTORCYCLE IDENTIFICATION

1 - 2
GEN
INFO
FEATURES
EAS00019
FEATURES
EAS00896
OUTLINE
The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera-
ture. In a conventional carburetor system, the air-fuel ratio of the mixture that is supplied to the
combustion chamber is created by the volume of the intake air and the fuel that is metered by the jet
used in the respective chamber.
Despite the same volume of intake air, the fuel volume requirement varies with the engine operating
conditions, such as acceleration, deceleration, or operation under a heavy load. Carburetors that
meter the fuel through the use of jets have been provided with various auxiliary devices, so that an
optimum air-fuel ratio can be achieved to accommodate the constant changes in the operating con-
ditions of the engine.
As the requirements for engines to deliver more performance and cleaner exhaust gases increase,
it becomes necessary to control the air-fuel ratio in a more precise and finely tuned manner. To
accommodate this need, this model has adopted an electronically controlled fuel injection (FI) sys-
tem in place of a conventional carburetor system. This system can achieve an optimum air-fuel ratio
required by the engine at all times by using a microprocessor that regulates the fuel injection volume
according to the engine operating conditions detected by various sensors.
Adoption of the FI system has resulted in a highly precise fuel supply, improved engine response,
better fuel economy, and reduced exhaust emissions. Furthermore, the air induction system (AI sys-
tem) has been placed under computer control together with the FI system in order to realize cleaner
exhaust gases.
1Air cut-off valve
2Air induction system
solenoid
3Engine trouble warn-
ing light
4Fuel tank
5Fuel pump
6Fuel hose
7Fuel injector
8Throttle position sen-
sor
9Intake air temperature
sensor
0Air filter case
AFuel injection system
relay
BBattery
CCatalytic converter
DECU
ELean angle cut-off
switch
FFast idle unit
GCrankshaft position
sensor
HCoolant temperature
sensor
ISpark plug
JIntake air pressure
sensor
KIgnition coil
1234 56
7890A
B
C
DEFGHI
J
K

1 - 3
GEN
INFO
FEATURES
EAS00897
FI SYSTEM
The fuel pump delivers fuel to the injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the injector at 324 kPa (3.24 kg/cm2, 46.1 psi) higher than the intake
manifold pressure. Accordingly, when the energizing signal from the ECU energizes the injector, the
fuel passage opens, causing the fuel to be injected into the intake manifold only during the time the
passage remains open. Therefore, the longer the length of time the injector is energized (injection
duration), the greater the volume of fuel that is supplied. Conversely, the shorter the length of time
the injector is energized (injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals that are input from
the throttle position sensor, crankshaft position sensor, intake air pressure sensor, intake air tem-
perature sensor, and coolant temperature sensor enable the ECU to determine the injection dura-
tion. The injection timing is determined through the signal from the crankshaft position sensor. As a
result, the volume of fuel that is required by the engine can be supplied at all times in accordance
with the driving conditions.
1Fuel pump
2Pressure regulator
3Fuel injector
4Throttle body
5Intake air temperature
sensor
6Throttle position sen-
sor
7Intake air pressure
sensor
8ECU
9Coolant temperature
sensor
0Crankshaft position
sensor
ÈFuel system
ÉAir system
ÊControl system
0
9
6
4
5
7
8
1
3
2
#1
È
É
Ê
Illustration is for reference only.

1 - 4
GEN
INFO
IMPORTANT INFORMATION
EAS00020
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 “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
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.
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 - 5
GEN
INFO
IMPORTANT INFORMATION
EAS00023
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.
EAS00024
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
EAS00025
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

1 - 6
GEN
INFO
CHECKING THE CONNECTIONS
EAS00026
CHECKING THE CONNECTIONS
Check the leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
•lead
•coupler
•connector
2. Check:
•lead
•coupler
•connector
Moisture →Dry with an air blower.
Rust/stains →Connect and disconnect sev-
eral times.
3. Check:
•all connections
Loose connection →Connect properly.
NOTE:
_
If the pin 1on the terminal is flattened, bend it
up.
4. Connect:
•lead
•coupler
•connector
NOTE:
_
Make sure all connections are tight.
5. Check:
•continuity
(with the pocket tester)
NOTE:
_
•If there is no continuity, clean the terminals.
•When checking the wire harness, perform
steps (1) to (3).
•As a quick remedy, use a contact revitalizer
available at most part stores.
Pocket tester
90890-03112

1 - 7
GEN
INFO
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.
Tool No. Tool name/Function Illustration
Slide hammer bolt
90890-01083
Weight
90890-01084
Slide hammer bolt
Weight
These tools are used to remove or install
the rocker arm shafts.
90890-01135
Crankcase separating tool
This tool is used to remove the crank-
shaft.
Attachment
90890-01243
Compressor
90890-04019
Valve spring compressor attachment
Valve spring compressor
These tools are used to remove or install
the valve assemblies.
90890-01268
Ring nut wrench
This tool is used to loosen or tighten the
steering ring nuts.
Pot
90890-01274
Bolt
90890-01275
Crankshaft installer pot
Crankshaft installer bolt
These tools are used to install the crank-
shaft.
90890-01304
Piston pin puller set
This tool is used to remove the piston pin.
90890-01325
Radiator cap tester
This tool is used to check the cooling sys-
tem.

1 - 8
GEN
INFO
SPECIAL TOOLS
T-handle
90890-01326
Holder
90890-01460
T-handle
Damper rod holder
These tools are used to hold the damper
rod holder when removing or installing
the damper rod.
90890-01352
Radiator cap tester adaptor
This tool is used to check the cooling sys-
tem.
90890-01362
Flywheel puller
This tool is used to remove the A.C. mag-
neto rotor.
Weight
90890-01367
Attachment
90890-01374
Fork seal driver weight
Fork seal driver attachment (ø43)
These tools are used to install the oil
seal, dust seal, and the outer tube bush-
ing of the front fork legs.
90890-01403
Steering nut wrench
This tool is used to loosen or tighten the
steering ring nuts.
90890-01496
Radiator tester adapter
This tool is used to check the cooling sys-
tem.
90890-01497
Radiator cap tester adapter
This tool is used to check the cooling sys-
tem.
90890-01701
Sheave holder
This tool is used to hold the A.C. magneto
rotor when loosen or tighten the A.C.
magneto rotor nut.
Tool No. Tool name/Function Illustration
M8 ×80 mm M8 × 60 mm M8 ×150 mm
60
80
150
M8
M8
M8

1 - 9
GEN
INFO
SPECIAL TOOLS
90890-03079
Thickness gauge
This tool is used to measure the valve
clearance.
90890-03081
Compression gauge
These tools are used to measure the
engine compression.
90890-03112
Pocket tester
This tool is used to check the electrical
system.
90890-03141
Timing light
This tool is used to check the ignition tim-
ing.
90890-03153
Pressure gauge
This tool is needed to measure fuel pres-
sure.
90890-03174
Digital circuit tester
This tool is used to check electrical sys-
tem.
90890-03176
Fuel pressure adapter
This tool is needed to measure fuel pres-
sure.
Driver
90890-04058
Installer
90890-04132
Middle driven shaft bearing driver
Mechanical seal installer
These tools are used to install the
mechanical seal.
Tool No. Tool name/Function Illustration