fuel YAMAHA TTR90 2003 User Guide

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 ~ 0.1 in) ----
Engine idle speed 1,400 ~ 1,600 r/min ----Item Standard Limit
MAINTENANCE SPECIFICATIONS
CC
D
A
E

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) 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
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 M6 × 1.0 3 5 0.5 3.6
MAINTENANCE SPECIFICATIONS

2 - 18
SPEC

CABLE ROUTING DIAGRAM
1
Clamp
2
Engine stop switch lead
3
Main switch lead
4
Start switch lead
5
Brake cable
6
Throttle cable
7
Fuel tank breather hose
8
Ignition coil
9
Wire harness
0
Starter relay
A
Starter motor lead
B
Crankcase breather hose
C
Starter motor lead
D
Neutral switch lead
E
CDI magneto lead
F
CDI unit
G
Fuel overflow hose
HSpark plug lead
IFuel hose
JCarburetor heater lead
KCarburetor breather hose
LCarburetor heater couplerMCDI magneto coupler
NCDI unit coupler
OCDI unit connector
PCDI unit lead
QThermo switch lead
RThermo switch
SStarting circuit cut-off relay
TStarting circuit cut-off relay lead
URectifier/regulator lead
VRectifier/regulator
WStarter relay lead
A AA
C C
D
B
B B
BF FF
EE
D
A - AB - BE - E
C
F - FG - GD
KK
QRÔ
8
E
H
˜ 2 3 4
6
5
4
3
2
1
J
I
H
G
F
E
D
CBA 0 Ï 9 8 Î K 7
S
W U
V
A
0
Í T 99
QP
PT
9 
Ò
ˆ Ø
Ç ı
Å
Ó
Œ
Â
E
GGA
P
O
NML 9
È
9
Ì
Ê
Ë
25 mm (1.0 in)
∏
‰

2 - 19
SPECCABLE ROUTING DIAGRAM
ÅPass the start switch lead, main
switch lead, engine stop switch
lead and throttle cable through
the cable guide.
ıPass the fuel tank breather hose
through the hose guide.
ÇPass the carburetor breather
hose through the hose guide.
ÎFasten the carburetor heater lead,
main switch lead, engine stop
switch lead and start switch lead.‰After fastening the CDI mag-
neto lead, cut off any excess
from the plastic locking tie end.
ÏFasten the battery leads to the
bracket with the plastic locking
tie. For fastening, pass the plas-
tic locking tie through the hole in
the bracket.
ÌAfter fastening the starter motor
lead, cut off any excess from the
plastic locking tie end.ÓAfter fastening the CDI mag-
neto lead, cut off any excess
from the plastic locking tie end.
ÈPosition the start switch coupler
and engine stop switch coupler
between the carburetor breather
hose and thermo switch.
ÔMake sure that the CDI unit lead
does not contact the thermo
switch bracket.
A AA
C C
D
B
B B
BF FF
EE
D
A - AB - BE - E
C
F - FG - GD
KK
QRÔ
8
E
H
˜ 2 3 4
6
5
4
3
2
1
J
I
H
G
F
E
D
CBA 0 Ï 9 8 Î K 7
S
W U
V
A
0
Í T 99
QP
PT
9 
Ò
ˆ Ø
Ç ı
Å
Ó
Œ
Â
E
GGA
P
O
NML 9
È
9
Ì
Ê
Ë
25 mm (1.0 in)
∏
‰

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS/
PERIODIC MAINTENANCE AND LUBRICATION
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
PERIODIC MAINTENANCE AND LUBRICATION
Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
* Fuel lineCheck fuel hoses for cracks or damage.
Replace if necessary.
Spark plugCheck condition.
Clean, regap or replace if necessary.
* ValvesCheck valve clearance.
Adjust if necessary.
Air filter Clean or replace if necessary.
* CarburetorCheck engine idling speed and starter operation.
Adjust if necessary.
Exhaust systemsCheck for leakage.
Retighten if necessary.
Replace gasket if necessary.
Engine oilCheck oil level and vehicle for oil leakage.
Correct if necessary.
Change. (Warm engine before draining.)
ClutchCheck operation.
Adjust or replace cable.
* Front brakeCheck operation.
Adjust brake lever free play and replace brake
shoes if necessary.Every ride
* Rear brakeCheck operation.
Adjust brake pedal free play and replace brake
shoes if necessary.Every ride
* WheelsCheck balance, runout, spoke tightness and for
damage.
Tighten spokes and rebalance, replace if
necessary.
* TiresCheck tread depth and for damage.
Replace if necessary.
Check air pressure.
Correct if necessary.
* Wheel bearingsCheck bearing for looseness or damage.
Replace if necessary.
* SwingarmCheck swingarm pivoting point for play.
Correct if necessary.
Lubricate with lithium soap base grease.
Drive chainCheck chain slack.
Adjust if necessary. Make sure that the rear wheel
is properly aligned.
Clean and lubricate.Every ride
* Steering bearingsCheck bearing play and steering for roughness.
Correct accordingly.
Lubricate with lithium soap base grease every 120
hours.
3

4 - 1
ENG

ENGINE
CARBURETOR
Extent of removal:
1
Carburetor removal
Extent of removal Order Part name Q’ty Remarks
CARBURETOR REMOVAL
Preparation for removal Fuel tank
1 Clamp (air filter joint) 1 Loosen the screw (air filter joint).
2 Carburetor heater lead 1
3 Air vent hose 1
4 Fuel hose 1
5 Bolt 2
6 Carburetor assembly 1
7 O-ring 1
8 Spacer 1
9 Carburetor top 1
10 Starter plunger assembly 1
1

CARBURETOR

4 - 6
ENGCARBURETOR
EC464600
Float
1. Inspect:
Float 1
Damage → Replace.
ASSEMBLY AND INSTALLATION
Carburetor
1. Install:
Pilot air screw 1
Note the following installation points:
Screw in the pilot air screw until it is lightly
seated.
Back out it by the specified number of
turns.
Pilot air screw:
1-3/4 turns out
2. Install:
Throttle valve 1
Starter 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.

4 - 7
ENGCARBURETOR
1. Measure:
Fuel level a
Use a fuel level gauge 1.
Out of specification → Adjust.
Fuel level gauge:
YM-1312-A/90890-01312
Fuel level:
2 ~ 3 mm (0.08 ~ 0.12 in) below
the float chamber line

4 - 8
ENGCYLINDER HEAD
CYLINDER HEAD
Extent of removal:1 Cylinder head removal
Extent of removal Order Part name Q’ty Remarks
CYLINDER HEAD REMOVAL
Preparation for removal Seat, fuel tank and rear fender
Exhaust pipe
Carburetor Refer to “CARBURETOR” section.
Air filter case and starter lever
1 Plug cap/spark plug 1/1
2 Crankshaft end cover/O-ring 1/1
3 Timing plug/O-ring 1/1
4 Camshaft sprocket cover/O-ring 1/1
5 Tappet cover (intake)/O-ring 1/1
6 Tappet cover (exhaust)/O-ring 1/1
7 Camshaft sprocket bolt/washer 1/1
Refer to “REMOVAL POINTS”. 8 Timing chain tensioner 1
9 Gasket 1
1

4 - 39
ENGCDI MAGNETO AND STARTER CLUTCH
CDI MAGNETO AND STARTER CLUTCH
Extent of removal:1 Pickup coil/stator removal2 Rotor removal
3 Starter clutch/wheel gear removal
Extent of removal Order Part name Q’ty Remarks
CDI MAGNETO AND STATOR
REMOVAL
Preparation for removal Fuel tank
Crankcase cover (left) Refer to “CLUTCH” section.
1 CDI magneto coupler 1
2 Pickup coil/stator assembly 1
3 Rotor nut 1
Use special tool.
Refer to “REMOVAL POINTS”. 4 Rotor 1
5 Woodruff key 1
6 Shaft 1
7 Idler gear 1
8 Starter clutch/wheel gear 1/1
1
2
3