EC020000
INTRODUCTION
Congratulations on your purchase of a
Yamaha TTR90. This model is the culmination
of Yamaha’s vast experience in the production
of pacesetting racing machines. It represents
the highest grade of craftsmanship and reli-
ability 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.
NOTE:
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
l
READ THIS MANUAL CAREFULLY FOR
INSTRUCTIONS ON HOW TO PROPERLY
OPERATE THIS MACHINE.
l
ADULT INSTRUCTION AND SUPERVI-
SION ARE REQUIRED.
l
THIS MODEL IS PROVIDED WITH A
POWER REDUCTION PLATE FOR THE
BEGINNING RIDER. DO NOT REMOVE
THIS ITEM UNTIL THE ADULT SUPERVI-
SOR HAS JUDGED THE RIDER TO BE
PROFICIENT.
l
WEIGHT OF THE RIDER SHOULD NOT
EXCEED 40 kg (88 lb).
l
ALWAYS WEAR A HELMET AND SUIT-
ABLE PROTECTIVE CLOTHING WHEN
RIDING.
l
DO NOT TOUCH ANY MOVING PARTS OR
HEATED AREAS.
l
ALWAYS PERFORM PRE-OPERATION
CHECKS. REFER TO PAGE 15.
l
THIS MACHINE IS DESIGNED TO CARRY
THE OPERATOR ONLY.
NO PASSENGERS.
l
THIS MACHINE IS DESIGNED OFF-ROAD
USE ONLY.
IT IS NOT SUITABLE FOR ON-ROAD USE.
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:
1 - 9
GEN
INFO
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
EC151000
“ENGINE STOP” SWITCH
Make sure that the engine stop switch 1 is
positioned to “ ”. The engine stop switch has
been equipped to ensure safety in an emer-
gency such when the machine is up set or
trouble takes place in the throttle system. The
engine will not start or run when the engine
stop switch is turned to “ ”.
EC153000
SHIFT PEDAL
The gear ratios of the constant-mesh 3 speed
transmission are ideally spaced. The gears
can be shifted by using the shift pedal 1 on
the left side of the engine.
EC154000
KICK STARTER
WARNING
Before starting the engine, be sure to shift
the transmission into neutral.
Rotate the kick starter 1 away from the
engine. Push the starter down lightly with your
foot until the gears engage, then kick smoothly
and forcefully to start the engine.
EC155001
THROTTLE GRIP
The throttle grip 1 is located on the right han-
dlebar; it accelerates or decelerates the
engine. For acceleration, turn the grip toward
you; for deceleration, turn it away from you.
EC156000
FRONT BRAKE LEVER
The front brake lever 1 is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
1 - 11
GEN
INFO
CONTROL FUNCTIONS/FUEL
FUEL TANK CAP
Remove the fuel tank cap 1 by turning
counter-clockwise.
WARNING
Do not overfill the fuel tank. Avoid spilling
fuel on the hot engine.
FUEL
Use regular gasoline. Always use fresh, name
brand gasoline.
WARNING
Do not overfill the fuel tank. Avoid spilling
fuel on the hot engine. Do not fill the fuel
tank above the bottom of the filler tube 1
as shown in the illustration or it may over-
flow when the fuel heats up later and
expands.
aFuel level
Recommended fuel:
UNLEADED FUEL RECOM-
MENDED
Fuel tank capacity:
Total:
4.1 L (0.90 lmp gal, 1.08 US gal)
Reserve:
0.5 L (0.11 lmp gal, 0.13 US gal)
GEN
INFO
1 - 12
STARTING AND OPERATION
STARTING AND OPERATION
CAUTION:
Prior to operating the machine, perform
steps listed in pre-operation check list.
WARNING
Never start your engine or let it run for any
length of time in a closed area. The exhaust
fumes are poisonous and can cause loss of
consciousness and death within a short
time. Always operate your machine in an
area with adequate ventilation.
STARTING A COLD ENGINE
WARNING
Before starting the engine, be sure to shift
the transmission into neutral.
1. Turn the fuel cock to “ON”.
2. Operate the starter (choke) and com-
pletely close the throttle grip.
3. Slide the “ENGINE STOP” switch to the
“”.
4. Kick the kick starter with full strength to
start the engine.
5. After the engine starts, warm up for one
or two minutes. Make sure the stater
(choke) is returned to the original position
before riding.
STARTING A WARM ENGINE
To start a warm engine, refer to the “Starting a
cold engine” section. The starter (choke)
should not be used. The throttle should be
opened slightly.
CAUTION:
See “Break-in Section” prior to operating
engine for the first time.WARMING UP
To get maximum engine life, always “warm-up”
the engine before starting off. Never acceler-
ate hard with a cold engine! To see whether or
not the engine is warm, see if it responds to
throttle normally with the stater (choke) turned
off.
WARNING
Before starting off, be sure to turn up or
remove the side stand.
Failure to retract the side stand completely
can result in a serious accident when you
try to turn a corner.
ENGINE BREAK-IN
1. Prior to starting, fill fuel tank with gasoline
and oil tank with specified oil.
2. Allow engine to warm up. Check engine
idling speed. Check operating controls
and engine stop switch operation.
3. Operate machine in lower gears at mod-
erate throttle setting for 3 ~ 5 minutes.
Check spark plug condition.
4. Allow engine to cool. Repeat procedure,
running for 5 minutes. Very briefly, shift to
higher gears and check full throttle
response. Check spark plug condition.
5. Allow engine to cool. Repeat procedure,
running for 5 minutes. Full throttle and
higher gears may be used, but avoid sus-
tained full throttle operation. Check spark
plug condition.
6. Allow engine to cool. Remove top end and
inspect. Remove “high” spots on piston
with No.600 grit, wet sandpaper.
Clean, and carefully reassemble.
7. Check entire unit for loose or misadjusted
fittings/controls/fasteners.
8. Re-start engine and check through entire
operating range thoroughly. Stop. Check
spark plug condition. Re-start. After 10 ~
15 minutes operation, machine is ready
to ride.
CAUTION:
After the break-in period, check every fit-
ting and fastener for looseness.
If any loose is found, retighten it securely.
3 - 3
INSP
ADJ
ENGINE/THROTTLE CABLE ADJUSTMENT/
AIR FILTER CLEANING
EC350000
ENGINE
EC35A001
THROTTLE CABLE ADJUSTMENT
1. Check:
l
Throttle grip free play
a
Out of specification
®
Adjust.
Throttle grip free play
a
:
3 ~ 5 mm (0.12 ~ 0.20 in)
2. Adjust:
l
Throttle grip free play
EC35G040
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.Throttle grip free play adjustment steps:
Turning in: Free play is increased.
Turning out: Free play is decreased.
l
Tighten the locknuts.
NOTE:
Before adjusting the throttle cable free play,
the engine idle speed should be adjusted.
lLoosen the locknut 1 on throttle cable.
lTurn the adjuster 2 in or out until the
specified free play is obtained.
WARNING
After adjusting, turn the handlebar to
right and left and make sure that the
engine idling does not run faster.
3 - 5
INSP
ADJ
ENGINE OIL LEVEL INSPECTION
1. Stand the motorcycle on a level surface.
NOTE:
l
When checking the oil level make sure that
the motorcycle is upright.
l
Place the motorcycle on a suitable stand.
WARNING
Never remove the oil tank cap just after
high speed operation. The heated oil could
spurt out causing danger. Wait until the oil
cools down to approximately 70 ˚C (158 ˚F).
2. Idle the engine more than 3 minutes
while keeping the motorcycle upright.
Then stop the engine and inspect the oil
level.
3. Remove:
l
Dipstick
1
4. Inspect:
l
Oil level
Oil level should be between maximum
a
and minimum
b
marks.
Oil level is low
®
Add oil to proper
level.
NOTE:
When inspecting the oil level, do not screw the
oil level gauge into the oil tank.
Insert the gauge lightly.
(For USA and CDN)
CAUTION:
l
Do not add any chemical additives.
Engine oil also lubricates the clutch and
additives could cause clutch slippage.
l
Do not allow foreign material to enter the
crankcase.
Recommended oil:
At –10 ˚C (10 ˚F) or higher
:
Yamalube 4 (10W30) or SAE
10W30 type SE/SF motor oil
At 5 ˚C (40 ˚F) or higher
õ
:
Yamalube 4 (20W40) or SAE
20W40 type SE/SF motor oil
010 30 50 70
90110
130
-20
-10 010
20 30 40
50
õ
˚C˚F
ENGINE OIL LEVEL INSPECTION
3 - 16
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
3. Check:
lSteering smooth action
Turn the handlebar lock to lock.
Unsmooth action ® Adjust steering ring
nut.
4. Adjust:
lSteering ring nut
Steering ring nut adjustment steps:
lRemove the front fender 1.
lRemove the handlebar and handle crown.
lLoosen the ring nut 2 using the ring nut
wrench 3.
Ring nut wrench:
YU-01268/90890-01268
lTighten the ring nut 4 using ring nut
wrench 5.
Ring nut wrench:
YM-33975/90890-01403
T R..
Ring nut (initial tightening):
38 Nm (3.8 m • kg, 27 ft • lb)
lLoosen the ring nut one turn.
lRetighten the ring nut using the ring nut
wrench.
T R..
Ring nut (final tightening):
1 Nm (0.1 m • kg, 0.7 ft • lb)
lCheck the steering shaft by turning it lock
to lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
lInstall the handle crown 6, handlebar 7,
and front fender.
2 3
5
4
NOTE:
Set the torque wrench to the ring nut
wrench so that they form a right angle.
WARNING
Avoid over-tightening.