2002 YAMAHA TTR90 warning

4 - 6
ENGCARBURETOR
EC464600
Float
1. Inspect:
lFloat 1
Damage ® Replace.
ASSEMBLY AND INSTALLATION
Carburetor
1. Install:
lPilot air screw 1
Note the following installation points:
lScrew in the pilot air screw until it is lightly
seated.
lBack out it by the specified number of
turns.
Pilot air screw:
1-3/4 turns out
2. Install:
lThrottle valve 1
lStarter plunger 2
NOTE:
Align the slit a of the throttle valve with the tab
b of the carburetor top.
FUEL LEVEL ADJUSTMENT
WARNING
Gasoline (fuel) and its vapors are highly
flammable and explosive. Keep away from
sparks, cigarettes, flames or other sources
of ignition.

5 - 1
CHAS
EC500000
CHASSIS
FRONT WHEEL AND REAR WHEEL
FRONT WHEEL AND FRONT BRAKE
FRONT WHEEL AND REAR WHEEL
Extent of removal:1 Front wheel removal2 Wheel bearing removal
3 Brake shoe plate assembly removal and disassembly
Extent of removal Order Part name Q’ty Remarks
FRONT WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
1 Bolt (brake cable holder) 1 Only loosening.
2 Brake cable 1 Disconnect at the lever side.
3 Wheel axle nut 1
4 Front wheel axle 1
5 Front wheel 1
6 Collar set 1
7 Brake shoe plate assembly 1
8 Oil seal 1
9Bearing
2Refer to “REMOVAL POINTS”.
2
31
3
5

5 - 3
CHASFRONT WHEEL AND REAR WHEEL
REAR WHEEL AND REAR BRAKE
Extent of removal:1 Rear wheel removal2 Wheel bearing removal
3 Brake shoe plate assembly removal and disassembly
Extent of removal Order Part name Q’ty Remarks
REAR WHEEL REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
1 Brake rod 1
2 Cotter pin 1
3 Nut (tension bar) 1
4 Bolt (tension bar) 1
5 Wheel axle nut 1
6 Rear wheel axle 1
7 Drive chain puller 2
8 Rear wheel 1
9 Collar (right) 1
10 Brake shoe plate assembly 1
231

5 - 6
CHASFRONT FORK
EC550000
FRONT FORK
Extent of removal:1 Front fork removal
Extent of removal Order Part name Q’ty Remarks
FRONT FORK REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Brake cable holder 1
2 Cap bolt 1
3 Adjuster 1 Only loosening.
4 Pinch bolt (under bracket) 1 Only loosening.
5 Front fork 1
1

5 - 10
CHASSTEERING
EC560000
STEERING
LS
LS
T R..TIGHTENING STEPS:
•Tighten ring nut.
38 Nm (3.8 m • kg, 27 ft • Ib)
•Loosen it completly
•Retighten it.
1 Nm (0.1 m • kg, 0.7 ft • Ib)
T R..40 Nm (4.0 m • kg, 29 ft • Ib)
5 9681076 43
21
Extent of removal:1 Under bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Front fork Refer to “FRONT FORK” section.
1 Steering stem bolt 1
2 Handle crown 1
3 Ring nut 1 Use special tool.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in
the CHAPTER 3.
4 Ball race cover 1
5 Under bracket 1
6 Bearing inner race 2
7 Upper bearing ball 19
8 Lower bearing ball 16
9 Dust seal 1
10 Bearing outer race 2
2
1

5 - 11
CHASSWINGARM
EC570000
SWINGARM
Extent of removal:1 Swingarm removal2 Rear shock absorber removal
Extent of removal Order Part name Q’ty Remarks
SWINGARM REMOVAL
WARNING
Support the machine securely so there is nodanger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Rear wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Rear fender
Drive chain
1 Cotter pin 2
2 Pin 2
3 Rear shock absorber 1
4 Pivot shaft 1 Hold the swingarm.
5 Swing arm 1
6 Chain guard 1
7 Chain case (upper) 1
8 Chain case (lower) 1
1
2

6 - 8
–+ELECCARBURETOR HEATING SYSTEM
The thermo switch circuit is open.
õThe thermo switch circuit is closed.
Test step Water temperature Continuity
1Less than 23 ± 3 ˚C
(73.4 ± 5.4 ˚F)YES
2More than 23 ± 3 ˚C
(73.4 ± 5.4 ˚F)NO
3More than 12 ± 4 ˚C
(53.6 ± 7.2 ˚F)NO
4Less than 12 ± 4 ˚C
(53.6 ± 7.2 ˚F)YES
Test steps 1 & 2: Heating phase
Test steps 3 & 4: Cooling phase
WARNING
lHandle the thermo switch with special
care.
lNever subject the thermo switch to
strong shocks. If the thermo switch is
dropped, replace it.
lCheck the thermo switch operation.
CARBURETOR HEATER INSPECTION
1. Inspect:
lCarburetor heater resistance
Out of specification ® Replace.
Tester (+) probe ®
Carburetor heater terminal 1
Tester (–) probe ®
Carburetor heater body 2
Carburetor
heater resistanceTester selector
position
6 ~ 10 W at
20˚C (68 ˚F)W ´ 1