Page 63 of 390
SPEC
2 - 4
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.03 mm
(0.0012 in)
Cylinder:
Bore size 47.000 ~ 47.005 mm
(1.8504 ~ 1.8506 in)47.05 mm
(1.8524 in)
Out of round limit ---- 0.05 mm
(0.0020 in)
Camshaft:
Drive method Chain drive (left) ----
Cam dimensions
Intake“A”25.428 ~ 25.528 mm
(1.0011 ~ 1.0050 in)25.400 mm
(1.0000 in)
“B”21.034 ~ 21.134 mm
(0.8281 ~ 0.8320 in)21.000 mm
(0.8268 in)
Exhaust“A”25.286 ~ 25.386 mm
(0.9955 ~ 0.9994 in)25.260 mm
(0.9945 in)
“B”21.047 ~ 21.147 mm
(0.8286 ~ 0.8326 in)21.017 mm
(0.8274 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)
MAINTENANCE SPECIFICATIONS
Page 67 of 390

SPEC
2 - 8 Crankshaft:
Crank width “A”42.95 ~ 43.00 mm
(1.691 ~ 1.693 in)----
Runout limit “C”---- 0.03 mm
(0.0012 in)
Big end side clearance “D”0.10 ~ 0.40 mm
(0.0039 ~ 0.0157 in)0.50 mm
(0.02 in)
Big end radial clearance “E”0.010 ~ 0.025 mm
(0.0004 ~ 0.0010 in)0.05 mm
(0.002 in)
Clutch:
Friction plate thickness 2.7 ~ 2.9 mm
(0.106 ~ 0.114 in)2.6 mm
(0.102 in)
Quantity 5 ----
Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ----
Quantity 4 ----
Warp limit ---- 0.2 mm
(0.008 in)
Clutch spring free length 26.2 mm (1.03 in) 24.2 mm
(0.95 in)
Quantity 4 ----
Clutch release method Inner push, cam push ----
Push rod bending limit ---- 0.5 mm
(0.02 in)
Automatic centrifugal clutch:
Clutch-in revolution 2,160 ~ 2,560 r/min ----
Clutch-stall revolution 3,300 ~ 3,800 r/min ----
Shifter:
Shifter type Cam drum and guide bar ----
Kick starter:
Type Ratchet type ----
Kick clip friction force 5.8 ~ 14.7 N
(0.59 ~ 1.50 kg, 1.3 ~ 3.3 lb)----
Carburetor:
I. D. mark 5HN1 01 ----
Main jet (M.J) #90 ----
Main air jet (M.A.J)ø 1.1 ----
Jet needle (J.N) 4E9-2 ----
Cutaway (C.A) 2.5 ----
Pilot outlet (P.O)ø 1.0 × 2.0 ----
Pilot jet (P.J) #12.5 ----
Valve seat size (V.S)ø 1.5 ----
Starter jet 1 (G.S.1) #37.5 ----
Pilot air screw 1-3/4 turns out ----
Float height (F.H) 15.5 ~ 16.5 mm (0.61 ~ 0.65 in) ----
Fuel level (F.L) 2 ~ 3 mm (0.08 ~ 0.10 in) ----
Engine idle speed 1,400 ~ 1,600 r/min ----Item Standard Limit
CC
D
A
E
MAINTENANCE SPECIFICATIONS
Page 72 of 390

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 76 of 390

SPEC
2 - 17
EC220001
GENERAL TORQUE SPECIFICATIONS
This chart specifies torque for standard fasten-
ers with standard I.S.O. pitch threads. Torque
specifications for special components or
assemblies are included in the applicable sec-
tions of this book. To avoid warpage, tighten
multi-fastener assemblies in a crisscross fash-
ion, in progressive stages, until full torque is
reached. Unless otherwise specified, torque
specifications call for clean, dry threads. Com-
ponents should be at room temperature.
A: Distance between flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
A
(Nut)B
(Bolt)TORQUE
SPECIFICATION
Nm m·kg ft·lb
10 mm
12 mm
14 mm
17 mm
19 mm
22 mm6 mm
8 mm
10 mm
12 mm
14 mm
16 mm6
15
30
55
85
1300.6
1.5
3.0
5.5
8.5
134.3
11
22
40
61
94
Unit Read Definition Measure
mm
cmmillimeter
centimeter10
-3 meter
10-2 meterLength
Length
kg kilogram 10
3 gram Weight
N Newton 1 kg
× m/sec
2 Force
Nm
m kgNewton meter
Meter kilogramN
× m
m
× kgTorque
Torque
Pa Pascal N/m
2Pressure
N/mm Newton per millimeter N/mm Spring rate
L
cm
3 Liter
Cubic centimeter—
—Volume or capacity
Volume or capacity
r/min Revolution per minute
—Engine speed
GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS
Page 112 of 390
2 - 18
SPECCABLE ROUTING DIAGRAM
CABLE ROUTING DIAGRAM
TT-R90
1Crankcase breather hose
2Wire harness
3CDI magneto lead
4Starter cable
5Carburetor heating lead
6Engine stop switch lead
7Thermo switch
8Thermo switch lead
9Spark plug lead0Throttle cable
ACable holder
BFuel tank breather hose
CBrake cable
ÈAfter fastening the starter cable, CDI magneto lead, wire harness and
thermo switch lead, cut off any excess from the plastic locking tie end.
ÉPass the ignition coil lead through the lead guide.
ÊFasten the engine stop switch lead with the plastic bands.
ËPass the brake cable through the cable guides.
12345
9
0
B A
6
CÈ
É
Ê
Ë
Ë
67
8
20 ~ 30 mm
(0.79 ~ 1.18 in)
Page 114 of 390
2 - 19
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
F K
7 ÈÊ
Ì
Ê
Í
ÎB - B C - C
D - DF - FE
É
Ë
D
D
B
D
A A B
B B
B
C
C C
CE
B D
B
D
F F F F
Page 116 of 390
2 - 20
SPECCABLE ROUTING DIAGRAM
ÈPass the fuel tank breather hose through the
cable guide.
ÉPass the throttle cable and engine stop switch
lead through the cable guide.
ÊPass the air vent hose through the hose guide.
ËFasten the CDI unit lead and rectifier/regulator
lead with the plastic clamp.
ÌAlign the tape on the rectifier/regulator lead with
the plastic clamp.
ÍAfter fastening the engine stop switch lead, cut
off any excess from the plastic locking tie end.ÎPass 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
F K
7 ÈÊ
Ì
Ê
Í
ÎB - B C - C
D - DF - FE
É
Ë
D
D
B
D
A A B
B B
B
C
C C
CE
B D
B
D
F F F F
Page 118 of 390
2 - 21
SPECCABLE ROUTING DIAGRAM
TT-R90E
1Crankcase breather hose
2CDI magneto lead
3Wire harness
4Thermo switch
5Thermo switch lead
6CDI unit lead
7Spark plug lead
8Starter cable
9Starter relay lead
0Starter motor leadAStarter motor
BThrottle cable
CBrake cable
DEngine stop switch lead
EMain switch lead
FStart switch lead
ÈPass the spark plug lead
through the lead guide.ÉMake sure that the starter
cable does not contact the
engine bracket.
ÊFasten the engine stop lead
with the plastic bands.
ËPass the brake cable through
the cable guide.
ÌFasten the start switch lead
with the plastic bands.
30 ~ 40 mm
(1.18 ~ 1.57 in)
A
20 ~30 mm
(0.79 ~ 1.18 in)B
C
D
E Ì
F
ËËÊ A875 4
6 3
2
1
È
É
A
0
9
10 ~ 20 mm
(0.39 ~ 0.79 in)