Page 18 of 364

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 E to H in 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 I to J in 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
E F
G H
IJ
GEN
INFOSPEC
INSP
ADJENG
CHAS–+ELEC
T R..
EM
LSM
LTNew
Page 32 of 364

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
1
and 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)
1
and 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.
Page 50 of 364

1 - 11
GEN
INFO
CONTROL FUNCTIONS
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor while filtering the fuel. The fuel cock
has the three positions:
OFF: With the lever in this position, fuel will
not flow. Always return the lever to this
position when the engine is not running.
ON: With the lever in this position, fuel flows
to the carburetor. Normal riding is done
with the lever in this position.
RES: This indicates reserve. If you run out of
fuel while riding, move the lever to this
position. FILL THE TANK AT THE
FIRST OPPORTUNITY. BE SURE TO
SET THE LEVER TO “ON” AFTER
REFUELING.
STARTER LEVER (CHOKE)
When cold, the engine requires a richer air/fuel
mixture for starting. A separate starter circuit,
which is controlled by the starter lever 1, sup-
plies this mixture.
Pull the lever out to open the circuit (for start-
ing) and push the lever in to close the circuit.
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.
1
TOOL KIT
Spark plug wrench
Spark plug wrench 1 is used to remove and
install the spark plug.
Screw driver
This tool is used for preventive maintenance
and minor repairs.
1
Page 63 of 364
SPEC
2 - 6 Stem runout limit ---- 0.02 mm
(0.0008 in)
Valve seat width IN 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
EX 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
Valve spring:
Free length IN 32.45 mm (1.28 in) 26.9 mm
(1.06 in)
EX 32.45 mm (1.28 in) 26.9 mm
(1.06 in)
Set length (valve closed) IN 24.2 mm (0.95 in) ----
EX 24.2 mm (0.95 in) ----
Compressed pressure
(installed) IN 138 ~ 158 N
(14.07 ~ 16.11 kg,
31.02 ~ 35.52 lb)----
EX 138 ~ 158 N
(14.07 ~ 16.11 kg,
31.02 ~ 35.52 lb)----
Tilt limit IN ---- 2.5˚/1.4 mm
(2.5˚/0.06 in)
EX ---- 2.5˚/1.4 mm
(2.5˚/0.06 in)
Direction of winding
(top view) IN Clockwise ----
EX Clockwise ---- Item Standard Limit
*
MAINTENANCE SPECIFICATIONS
Page 67 of 364

SPEC
2 - 10 Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Cylinder head nut M8
×
1.25 4 22 2.2 16
Cylinder head bolt M6
×
1.0 2 10 1.0 7.2
Spark plug M10
×
1.0 1 13 1.3 9.4
Camshaft sprocket cover bolt M6
×
1.0 2 7 0.7 5.1
Tappet cover M45
×
1.5 2 18 1.8 13
Exhaust pipe stud bolt M6
×
1.0 2 7 0.7 5.1
Rotor nut M12
×
1.25 1 48 4.8 35
Timing chain guide (rear) M6
×
1.0 2 10 1.0 7.2
Valve clearance adjust screw locknut M5
×
0.5 2 7 0.7 5.1
Camshaft sprocket M8
×
1.25 1 20 2.0 14
Camshaft bearing retainer M6
×
1.0 1 10 1.0 7.2
Timing chain tensioner cap bolt M8
×
1.25 1 8 0.8 5.8
Timing chain tensioner M6
×
1.0 2 10 1.0 7.2
Oil pump M6
×
1.0 2 7 0.7 5.1
Drain bolt M12
×
1.5 1 20 2.0 14
Carburetor joint (cylinder head side) M6
×
1.0 2 7 0.7 5.1
Carburetor joint (carburetor side) M6
×
1.0 2 7 0.7 5.1
Air filter case M6
×
1.0 2 7 0.7 5.1
Exhaust pipe M6
×
1.0 2 7 0.7 5.1
Exhaust pipe protector M6
×
1.0 7 7 0.7 5.1
Silencer M8
×
1.25 1 24 2.4 17
Silencer protector M5
×
0.8 2 4 0.4 2.9
Crankcase M6
×
1.0 9 10 1.0 7.2
Crankcase cover (left) (TT-R90) M6
×
1.0 8 7 0.7 5.1
(TT-R90E) M6
×
1.0 8 10 1.0 7.2
Drive sprocket cover M6
×
1.0 2 7 0.7 5.1
Crankcase cover (right) (TT-R90) M6
×
1.0 9 7 0.7 5.1
(TT-R90E) M6
×
1.0 9 10 1.0 7.2
Timing plug M14
×
1.5 1 7 0.7 5.1
Crankshaft end cover M32
×
1.5 1 7 0.7 5.1
Cylinder head stud bolt M8
×
1.25 4 13 1.3 9.4
Kick crank M6
×
1.0 1 10 1.0 7.2
Starter clutch and rotor (TT-R90E) M6
×
1.0 3 14 1.4 10
Primary drive gear M12
×
1.0 1 50 5.0 36
Pressure plate M5
×
0.8 4 6 0.6 4.3
Clutch boss M14
×
1.0 1 70 7.0 50
Main axle bearing retainer M6
×
1.0 1 10 1.0 7.2
Shift pedal M6
×
1.0 1 8 0.8 5.8
Clutch adjust screw locknut M6
×
1.0 1 8 0.8 5.8
Pickup coil M6
×
1.0 2 10 1.0 7.2
Stator assembly M6
×
1.0 3 10 1.0 7.2
Neutral switch (TT-R90E) M10
×
1.25 1 18 1.8 13
MAINTENANCE SPECIFICATIONS
Page 70 of 364

SPEC
2 - 13
NOTE:
1. First, tighten the ring nut approximately 38 Nm (3.8 m • kg, 27 ft • lb) by using the ring nut
wrench and turn the steering right and left a few times; then loosen the ring nut one turn.
2. Retighten the ring nut 1 Nm (0.1 m • kg, 0.7 ft • lb).
-marked portion shall be checked for torque tightening after break-in or before each ride.Part to be tightened Thread size Q’tyTightening torque
Nm m•kg ft•lb
Engine mounting:
Engine and frame (front-upper) M8 × 1.25 1 30 3.0 22
Engine and frame (rear-upper) M8 × 1.25 1 26 2.6 19
Engine and frame (rear-lower) M10 × 1.25 1 48 4.8 35
Starter cable and frame M11 × 1.25 1 1 0.1 0.7
Pivot shaft and nut M10 × 1.25 1 30 3.0 22
Handle crown and steering shaft M10 × 1.25 1 40 4.0 29
Front fork cap bolt M20 × 1.0 2 40 4.0 29
Under bracket and front fork M10 × 1.25 2 33 3.3 24
Damper rod bolt M8 × 1.25 2 20 2.0 14
Handle crown and handlebar holder (lower) M10 × 1.25 2 40 4.0 29
Handlebar holder (upper) (TT-R90) M6 × 1.0 4 13 1.3 9.4
(TT-R90E) M8 × 1.25 4 23 2.3 17
Front brake cable holder and front fork M6 × 1.0 2 7 0.7 5.1
Steering ring nut M25 1 Refer to NOTE.
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and frame M6 × 1.0 2 7 0.7 5.1
Grab bar and frame M6 × 1.0 4 13 1.3 9.4
Brake lever mounting (bolt) M6 × 1.0 1 3 0.3 2.2
Brake lever mounting (nut) M6 × 1.0 1 4 0.4 2.9
Front brake camshaft lever and camshaft M6 × 1.0 1 7 0.7 5.1
Rear brake camshaft lever and camshaft M6 × 1.0 1 7 0.7 5.1
Front wheel axle nut M10 × 1.25 1 35 3.5 25
Rear brake shoe plate tension bar M8 × 1.25 2 26 2.6 19
Wheel drive hub and driven sprocket M8 × 1.25 4 25 2.5 18
Rear wheel axle nut M12 × 1.25 1 60 6.0 43
Wheel nipple (spoke)—64 2 0.2 1.4
Drive chain guard M5 × 0.8 2 4 0.4 2.9
Drive chain support M5 × 0.8 3 4 0.4 2.9
Chain puller locknut M6 × 1.0 2 7 0.7 5.1
Footrest and frame M8 × 1.25 2 30 3.0 22
Battery box (TT-R90E) M6 × 1.0 3 5 0.5 3.6
MAINTENANCE SPECIFICATIONS
Page 110 of 364
2 - 18
SPEC
CABLE ROUTING DIAGRAM
TT-R90
1
Crankcase breather hose
2
Wire harness
3
CDI magneto lead
4
Starter cable
5
Carburetor heating lead
6
Engine stop switch lead
7
Thermo switch
8
Thermo switch lead
9
Spark plug lead
0
Throttle cable
A
Cable holder
B
Fuel tank breather hose
C
Brake cable
Å
After fastening the starter cable, CDI magneto lead, wire harness and
thermo switch lead, cut off any excess from the plastic locking tie end.
ı
Pass the ignition coil lead through the lead guide.
Ç
Fasten the engine stop switch lead with the plastic bands.
Î
Pass the brake cable through the cable guides.
12345
9
0
B A
6
C 1Å
ı
Ç
Î
Î
A
A
67
8
20 ~ 30 mm
(0.79 ~ 1.18 in)
CABLE ROUTING DIAGRAM
Page 114 of 364
2 - 20
SPEC
Å
Pass the fuel tank breather hose through the
cable guide.
ı
Pass the throttle cable and engine stop switch
lead through the cable guide.
Ç
Pass the air vent hose through the hose guide.
Î
Fasten the CDI unit lead and rectifier/regulator
lead with the plastic clamp.
‰Align the tape on the rectifier/regulator lead with
the plastic clamp.
ÏAfter fastening the engine stop switch lead, cut
off any excess from the plastic locking tie end.ÌPass the CDI unit lead through the lead guide.
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 ÅÇ
‰
Ç
Ï
Ì
B - B C - C
D - DF - FE
ı
Î
D
D
B
D
A A B
B B
B
C
C C
CE
B D
B
D
F F F F
CABLE ROUTING DIAGRAM