2002 YAMAHA TTR90 ignition

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
MAINTENANCE RECORD ....................... 6-9

1 - 7
GEN
INFO
SPECIAL TOOLS
YM-1312-A, 90890-01312Fuel level gauge
This gauge is used to measure the fuel level in the
float chamber.YM-1312-A 90890-01312
YM-1326, 90890-01326 T-handle
This tool is used for holding the damper rod holder
when removing or installing the damper rod holder.YM-1326 90890-01326
90890-01186 Fork seal driver attachment
This tool is used to installing the oil seal.90890-01186
YM-8035, 90890-01311 Valve adjusting tool
This tool is necessary for adjusting valve clearance.YM-8035 90890-01311
YM-33963, 90890-01184 Fork seal driver weight
This tool is used to installing the oil seal.YM-33963 90890-01184
YM-34487
90890-06754Dynamic spark tester
Ignition checker
This instrument is necessary for checking the ignition
system components.YM-34487 90890-06754
YM-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.YM-33975 90890-01403
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
YS-1880-A, 90890-01701 Sheave holder
This tool is used for when loosening or tightening the
flywheel magneto securing nut.YS-1880-A 90890-01701
Part number Tool name/How to use Illustration

SPEC
2 - 3
Brake:
Front brake type Drum brake
Operation Right hand operation
Rear brake type Drum brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 110 mm (4.33 in)
Rear wheel travel 93 mm (3.66 in)
Electrical:
Ignition system CDI magneto
GENERAL SPECIFICATIONS

SPEC
2 - 14
EC212300
ELECTRICAL
Item Standard Limit
CDI:
Magneto-model/manufacturer F5HN 00/YAMAHA ----
Source coil resistance (color) 688 ~ 1,032 W at 20 ˚C (68 ˚F)
(Brown – Green)----
Pickup coil resistance (color) 248 ~ 372 W at 20 ˚C (68 ˚F)
(Red – White)----
CDI unit-model/manufacturer 4GL-20/YAMAHA ----
Ignition coil:
Model/manufacturer 4KJ-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.18 ~ 0.28 W at 20 ˚C (68 ˚F) ----
Secondary winding resistance 6.3 ~ 9.5 kW at 20 ˚C (68 ˚F) ----
Spark plug cap:
Type Resin ----
Resistance 10 kW at 20 ˚C (68 ˚F) ----
MAINTENANCE SPECIFICATIONS

2 - 16
SPECCABLE ROUTING DIAGRAM
CABLE ROUTING DIAGRAM
1Crankcase breather hose
2Wire harness
3CDI magneto lead
4Starter cable
5Carburetor heating lead
6Engine stop switch lead
7Thermo switch
8Thermo switch lead
9Spark plug lead
0Throttle cableACable holder
BFuel tank breather hose
CBrake cable
After fastening the starter cable, CDI magneto lead, wire harness and
thermo switch lead, cut off any excess from the plastic locking tie end.
õPass the ignition coil lead through the lead guide.
‚Fasten the engine stop switch lead with the plastic bands.
ëPass the brake cable through the cable guides.
12345
9
0
B A
6
C 1
õ
‚
ë
ë
A
A
67
8
20 ~ 30 mm
(0.79 ~ 1.18 in)

2 - 17
SPECCABLE ROUTING DIAGRAM
1Cable guide
2Brake cable
3Throttle cable
4Fuel tank breather hose
5Engine stop switch lead
6Air vent hose
7Air intake duct
8Ignition coil
9Cable guide
0Wire harness
ADamperBCDI unit lead
CCDI unit
DRectifier/regulator lead
ERectifier/regulator
FCrankcase breather hose
GCarburetor breather hose
HSpark plug lead
IFuel hose
JStarter cable
KCDI magneto lead
LThermo switch
A
123
4
5
6
7
8
9
0A
C
E B
F G H I
6
6 J L
5
H
B8 K
7 ‚
ä
‚
ì
í
B - B C - C
D - DF - FE
õ
ë
D
D
B
D
A A B
B B
B
C
C C
CE
B D
B
D
F F F F

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.

6 - 1
–+ELECELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1CDI magneto
2CDI unit
3Ignition coil
4Spark plug
5“ENGINE STOP” switch
6Thermo switch
7Carburetor heater
8Rectifier/regulatorCOLOR CODE
B...................... Black
Br .................... Brown
G ..................... Green
O ..................... Orange
R ..................... Red
W..................... White
EC612000
WIRING DIAGRAM
G/WB/RW/LW/RBr G
RW
WB
Y/R
O
BO
B
B
BY/RY
WY/RB
W
Y
B
GG/W
B/W
B/W
BrB/RWWWY
OO
BBW/LY/RR
W
B
B
B
W/R
Y/R
OFF
RUN
B
Y/R
B
B
Y
Y
1
23
4
5 6
7 8
B/R ................... Black/Red
B/W .................. Black/White
G/W.................. Green/White
W/L .................. White/Blue
W/R .................. White/Red
6