Yamaha TT-R90(R) User manual

TT-R90R
5HN-28199-13
LIT-11626-16-27
OWNER’S SERVICE MANUAL

EC010000
TT-R90R
OWNER’S SERVICE MANUAL
©2002 by Yamaha Motor Corporation, U.S.A.
1st Edition, April 2002
All rights reserved. Any reprinting or
unauthorized use without the written
permission of Yamaha Motor Corporation
U.S.A. is expressly prohibited.
Printed in Japan
P/N. LIT-11626-16-27

INTRODUCTION
Congratulations on your purchase of a
Yamaha TT-R90R. This model is the culmina-
tion of Yamaha’s vast experience in the pro-
duction of pacesetting racing machines. It
represents the highest grade of craftsmanship
and reliability that have made Yamaha a
leader.
This manual explains operation, inspection,
basic maintenance and tuning of your
machine. If you have any questions about this
manual or your machine, please contact your
Yamaha dealer.
N
OTE:
As improvements are made on this model,
some data in this manual may become out-
dated. If you have any questions, please con-
sult your Yamaha dealer.
WARNING
●
READ THIS MANUAL CAREFULLY FOR
INSTRUCTIONS ON HOW TO PROPERLY
OPERATE THIS MACHINE.
●
ADULT INSTRUCTION AND SUPERVI-
SION ARE REQUIRED.
●
WEIGHT OF THE RIDER SHOULD NOT
EXCEED 40 kg (88 lb).
●
ALWAYS WEAR A HELMET AND SUIT-
ABLE PROTECTIVE CLOTHING WHEN
RIDING.
●
DO NOT TOUCH ANY MOVING PARTS OR
HEATED AREAS.
●
ALWAYS PERFORM PRE-OPERATION
CHECKS. REFER TO PAGE 15.
●
THIS MACHINE IS DESIGNED TO CARRY
THE OPERATOR ONLY.
NO PASSENGERS.
●
THIS MACHINE IS DESIGNED OFF-ROAD
USE ONLY.
IT IS NOT SUITABLE FOR ON-ROAD USE.

IMPORTANT NOTICE
This machine is designed for off-road use only
by young operators under adult instruction and
supervision. It is illegal for this machine to be
operated on any public street, road, or high-
way.
Off-road use on public lands may be illegal.
Please check local regulations before riding.
1. GASOLINE IS HIGHLY FLAMMABLE:
* Always turn off the engine when
refueling.
* Take care not to spill on the engine
or exhaust pipe/muffler, when refu-
eling.
* Never refuel while smoking or in
the vicinity of an open flame.
2. If you should swallow some gasoline
or inhale a lot of gasoline vapor, or
allow some gasoline to get in your
eye(s), see your doctor immediately.
If any gasoline spills on your skin or
clothing, immediately wash it with
soap and water, and change your
clothes.
3. Always turn off the engine before
leaving the machine unattended.
When parking the machine, note the
following:
* The engine and exhaust pipe(s)/
muffler(s) may be hot. Park the
machine in a place where pedestri-
ans or children are not likely to
touch the machine.
* Do not park the machine on a slope
or soft ground; the machine may
overturn.
SAFETY INFORMATION

4. When transporting the machine in
another vehicle, be sure is kept
upright and that the fuel cock is
turned to the “OFF”. If it should lean
over, gasoline may leak out of the car-
buretor or fuel tank.
5. Never start your engine or let it run for
any length of time in a closed area.
The exhaust fumes are poisonous and
may cause loss of consciousness and
death within a short time. Always
operate your machine in an area with
adequate ventilation.
6. Always wear a helmet, gloves, boots,
trousers, and jacket for motocross
riding.

SAFETY INFORMATION
1. Don’t ride it on the street.
2. Don’t run the engine inside a building.
3. This is a one-seater motorbike. Don’t give
any person a ride.
4. Let’s learn how to ride properly. Ask your
parents for any question.
5. When riding the machine, be sure to wear
the protective apparel as illustrated.
1 Helmet
2 Goggles
3 Mouth guard
4 Gloves
5 Boots
6 Motocross pants
7 Long sleeved trainer

6. When going for riding, be sure to be with
your family.
Never go alone.
7. Before riding the machine, ask your par-
ents to check the machine very carefully.
8. Don’t touch the areas shown, or you’ll get
burnt in the hand.
9. Don’t touch rotating or moving parts.
10. Before starting the engine, be sure to shift
the transmission into neutral.

EC080000
HOW TO USE
THIS MANUAL
EC081000
PARTICULARLY IMPORTANT
INFORMATION
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 machine
operator, a bystander, or a person inspecting
or repairing the machine.
A CAUTION indicates special precautions that
must be taken to avoid damage to the
machine.
NOTE:
A NOTE provides key information to make pro-
cedures easier or clearer.
EC082000
FINDING THE REQUIRED PAGE
1. This manual consists of six chapters;
“General Information”, “Specifications”,
“Regular inspection and adjustments”,
“Engine”, “Chassis”and “Electrical”.
2. The table of contents is at the beginning
of the manual. Look over the general lay-
out of the book before finding then
required chapter and item.
Bend the book at its edge, as shown, to
find the required fore edge symbol mark
and go to a page for required item and
description.
WARNING
CAUTION:

EC083000
MANUAL FORMAT
All of the procedures in this manual are organized in a sequential, step-by-step format. The informa-
tion has been complied to provide the mechanic with an easy to read, handy reference that contains
comprehensive explanations of all disassembly, repair, assembly, and inspection operations.
In this revised format, the condition of a faulty component will precede an arrow symbol and the
course of action required will follow the symbol, e.g.
●
Bearings
Pitting/damage → Replace.
EC084002
HOW TO READ DESCRIPTIONS
To help identify parts and clarify procedure steps, there are exploded diagrams at the start of each
removal and disassembly section.
1. An easy-to-see exploded diagram 1 is provided for removal and disassembly jobs.
2. Numbers 2 are given in the order of the jobs in the exploded diagram. A number that is
enclosed by a circle indicates a disassembly step.
3. An explanation of jobs and notes is presented in an easy-to-read way by the use of symbol
marks 3 . The meanings of the symbol marks are given on the next page.
4. A job instruction chart 4 accompanies the exploded diagram, providing the order of jobs,
names of parts, notes in jobs, etc.
5. Extent of removal 5 is provided in the job instruction chart to save the trouble of an unneces-
sary removal job.
6. For jobs requiring more information, the step-by-step format supplements 6 are given in addi-
tion to the exploded diagram and job instruction chart.

ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols 1 to 6 are designed as
thumb tabs to indicate the chapter’s number
and content.
1 General information
2 Specifications
3 Regular inspection and adjustments
4 Engine
5 Chassis
6 Electrical
Illustrated symbols 7 to D are used to identify
the specifications appearing in the text.
7 With engine mounted
8 Special tool
9 Filling fluid
0 Lubricant
A Tightening
B Specified value, Service limit
C Engine speed
D Resistance ( Ω ), Voltage (V), Electric current (A)
Illustrated symbols Eto Hin the exploded
diagram indicate grade of lubricant and loca-
tion of lubrication point.
EApply engine oil
FApply molybdenum disulfide oil
GApply lightweight lithium-soap base grease
HApply molybdenum disulfide grease
Illustrated symbols Ito Jin the exploded
diagrams indicate where to apply a locking
agent and when to install new parts.
IApply locking agent (LOCTITE®)
JUse new one
12
34
56
78
90
AB
CD
EF
GH
IJ
GEN
INFO SPEC
INSP
ADJ ENG
CHAS
–+
ELEC
T
R
.
.
EM
LS M
LT New

INDEX
GENERAL INFORMATION 1
SPECIFICATIONS SPEC 2
REGULAR INSPECTION AND ADJUSTMENTS 3
ENGINE ENG 4
CHASSIS CHAS 5
ELECTRICAL ELEC 6
GEN
INFO
INSP
ADJ
–+

CONTENTS
CHAPTER 1
GENERAL INFORMATION
DESCRIPTION .......................................... 1-1
MACHINE IDENTIFICATION .................... 1-2
IMPORTANT INFORMATION ................... 1-3
CHECKING OF CONNECTION ................. 1-5
SPECIAL TOOLS ...................................... 1-6
CONTROL FUNCTIONS ........................... 1-9
FUEL ....................................................... 1-11
STARTING AND OPERATION ............... 1-12
CHAPTER 2
SPECIFICATIONS
GENERAL SPECIFICATIONS ................... 2-1
MAINTENANCE SPECIFICATIONS ......... 2-4
GENERAL TORQUE
SPECIFICATIONS ................................... 2-15
DEFINITION OF UNITS ........................... 2-15
CABLE ROUTING DIAGRAM ................. 2-16
CHAPTER 3
REGULAR INSPECTION AND
ADJUSTMENTS
MAINTENANCE INTERVALS ................... 3-1
PERIODIC MAINTENANCE AND
LUBRICATION .......................................... 3-1
PRE-OPERATION INSPECTION AND
MAINTENANCE ........................................ 3-2
ENGINE ..................................................... 3-3
CHASSIS ................................................. 3-11
ELECTRICAL .......................................... 3-19

CHAPTER 4
ENGINE
CARBURETOR ......................................... 4-1
CYLINDER HEAD ..................................... 4-8
CAMSHAFT AND ROCKER ARMS ........ 4-13
VALVES AND VALVE SPRINGS ........... 4-16
CYLINDER AND PISTON ....................... 4-21
CLUTCH .................................................. 4-27
KICK AXLE ............................................. 4-33
SHIFT SHAFT ......................................... 4-34
OIL PUMP ............................................... 4-36
CDI MAGNETO ....................................... 4-39
CRANKCASE AND CRANKSHAFT ....... 4-41
SHIFT FORK, SHIFT CAM AND
TRANSMISSION ..................................... 4-44
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL ....... 5-1
FRONT FORK ........................................... 5-6
HANDLEBAR ............................................ 5-9
STEERING .............................................. 5-10
SWINGARM ............................................ 5-11
CHAPTER 6
ELECTRICAL
ELECTRICAL COMPONENTS AND
WIRING DIAGRAM ................................... 6-1
IGNITION SYSTEM ................................... 6-2
CARBURETOR HEATING SYSTEM ........ 6-6
NOISE REGULATION ............................... 6-9
MAINTENANCE RECORD ........................ 6-9

1 - 1
GEN
INFO
DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1“ENGINE STOP”button
2Front brake lever
3Throttle grip
4Fuel tank cap
5Kick starter
6Fuel tank
7Air cleaner
8Rear brake pedal
9Fuel cock
0Starter lever (choke)
ADrive chain
BShift pedal
CFront fork
N
OTE:
●The machine you have purchased may differ
slightly from those shown in the following.
●Designs and specifications are subject to
change without notice.
1

1 - 2
GEN
INFO
MACHINE IDENTIFICATION
EC120001
MACHINE IDENTIFICATION
There are two significant reasons for knowing
the serial number of your machine:
1. When ordering parts, you can give the
number to your Yamaha dealer for posi-
tive identification of the model you own.
2. If your machine is stolen, the authorities
will need the number to search for and
identify your machine.
EC121001
VEHICLE IDENTIFICATION NUMBER
The vehicle identification number 1is
stamped on the right of the steering head pipe.
ENGINE SERIAL NUMBER
The engine serial number 1is stamped into
the elevated part of the left-side of the engine.
EC124000
MODEL LABEL
The model label 1is affixed to the frame
under the rider’s seat. This information will be
needed to order spare parts.
1
1

1 - 3
GEN
INFO
IMPORTANT INFORMATION
EC130000
IMPORTANT INFORMATION
EC131002
PREPARATION FOR REMOVAL AND
DISASSEMBLY
1. Remove all dirt, mud, dust, and foreign
material before removal and disassem-
bly.
When washing the machine with high
pressured water, cover the parts as fol-
lows.
●Silencer exhaust port
2. Use proper tools and cleaning equip-
ment. Refer to “SPECIAL TOOLS”sec-
tion.
3. When disassembling the machine, keep
mated parts together. They include
gears, cylinders, pistons, and other
mated parts that have been “mated”
through normal wear. Mated parts must
be reused as an assembly or replaced.
4. During the machine disassembly, clean
all parts and place them in trays in the
order of disassembly. This will speed up
assembly time and help assure that all
parts are correctly reinstalled.
5. Keep away from fire.

1 - 4
GEN
INFO
IMPORTANT INFORMATION
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for
assembly and adjustment.
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should
be replaced when an engine is over-
hauled. All gasket surfaces, oil seal lips,
and O-rings must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the
oil seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates 1and cotter pins
must be replaced when they are
removed. Lock tab(s) should be bent
along the bolt or nut flat(s) after the bolt
or nut has been properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing(s) 1and oil seal(s) 2
with their manufacturer’s marks or num-
bers facing outward. (In other words, the
stamped letters must be on the side
exposed to view.) When installing oil
seal(s), apply a light coating of light-
weight lithium base grease to the seal
lip(s). Oil the bearings liberally when
installing.
CAUTION:
Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.

1 - 5
GEN
INFO
IMPORTANT INFORMATION/
CHECKING OF CONNECTION
EC136000
CIRCLIPS
1. All circlips should be inspected carefully
before reassembly. Always replace pis-
ton pin clips after one use. Replace dis-
torted circlips. When installing a circlip
1, make sure that the sharp-edged cor-
ner 2is positioned opposite to the thrust
3it receives. See the sectional view.
4Shaft
CHECKING OF CONNECTION
Dealing with stains, rust, moisture, etc. on the
connector.
1. Disconnect:
●Connector
2. Dry each terminal with an air bower.
3. Connect and disconnect the connector
two or three times.
4. Pull the lead to check that it will not come
off.
5. If the terminal comes off, bend up the pin
1and reinsert the terminal into the con-
nector.
6. Connect:
●Connector
N
OTE:
The two connectors “click”together.
7. Check for continuity with a tester.
N
OTE:
●If there in no continuity, clean the terminals.
●Be sure to perform the steps 1 to 7 listed
above when checking the wireharness.
●For a field remedy, use a contact revitalizer
available on the market.
●Use the tester on the connector as shown.