engine YAMAHA TTR90 2002 Owner's Manual

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:
l1. 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).
l-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 40 4.0 29
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) M6 ´ 1.0 4 13 1.3 9.4
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
Chain case M5 ´ 0.8 5 4 0.4 2.9
Chain puller locknut M6 ´ 1.0 2 3 0.3 2.2
Footrest and frame M8 ´ 1.25 2 30 3.0 22
MAINTENANCE SPECIFICATIONS

2 - 15
SPEC
GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS
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
(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
A: Distance between flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
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

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

2 - 18
SPECCABLE ROUTING DIAGRAM
Pass the fuel tank breather hose through the
cable guide.
õPass the throttle cable and engine stop switch
lead through the cable guide.
‚Pass the air vent hose through the hose guide.
ëFasten the CDI unit lead and rectifier/regulator
lead with the plastic clamp.
äAlign the tape on the rectifier/regulator lead with
the plastic clamp.
ìAfter fastening the engine stop switch lead, cut
off any excess from the plastic locking tie end.íPass 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 ‚
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

3 - 1
INSP
ADJMAINTENANCE 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
3

3 - 2
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
*: Since these items requires special tools data and technical skills, they should be serviced.
*1: For USA
SERVICE NOTES:
No. 1. DRIVE CHAIN: In addition to tension and alignment, chain must be lubricated every
0.5 ~ 1.0 hour. If unit is subjected to extremely hard usage and wet weather riding, chain
must be checked constantly. See “Lubrication Intervals” for additional details.
No. 2. AIR FILTER: Remove and clean filter every 20 ~ 40 hours.
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
* Chassis fastenersMake sure that all nuts, bolts and screws are
properly tightened.
Tighten if necessary.
SidestandCheck operation.
Lubricate and repair if necessary.
* Spark arrester*1Clean.
* Front forkCheck operation and for oil leakage.
Correct accordingly.
*Rear shock
absorber assemblyCheck operation and shock absorber for oil
leakage.
Replace shock absorber assembly if necessary.
Item Routine Page
Brake Check operation/adjustment. P3-11
Engine oil Change oil as required. P3-5 ~ 7
Drive chain Check alignment/adjustment/lubrication. P3-12
Spark plug Check color/condition. P3-19
Throttle Check for proper throttle cable operation. P3-3
Air filter Foam type – must be clean and damp oil always P3-3 ~ 4
Wheels and tires Check pressure/runout/spoke tightness/bead stopper/axle nuts. P3-15 ~ 17
Fittings/fasteners Check all – tighten as necessary. P2-13Dealer
NoteItem Checks and maintenance jobsInitial Every
10 hours
(1 month)60 hours
(6 months)120 hours
(12 months)
3

3 - 3
INSP
ADJENGINE/THROTTLE CABLE ADJUSTMENT/
AIR FILTER CLEANING
EC350000
ENGINE
THROTTLE CABLE ADJUSTMENT
1. Check:
lThrottle grip free play a
Out of specification ® Adjust.
Throttle grip free play a:
3 ~ 5 mm (0.12 ~ 0.20 in)
2. Adjust:
lThrottle grip free play
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.Throttle grip free play adjustment steps:
NOTE:
Before adjusting the throttle cable free play,
the engine idle speed should be adjusted.
lLoosen the locknut 1 on throttle cable.
lTurn the adjuster 2 in or out until the
specified free play is obtained.
Turning in: Free play is increased.
Turning out: Free play is decreased.
lTighten the locknut.
WARNING
After adjusting, turn the handlebar to
right and left and make sure that the
engine idling does not run faster.

3 - 4
INSP
ADJ
AIR FILTER CLEANING
1. Install:
lAir scoop (right) 1
2. Install:
lAir filter case cover 1
3. Clean:
lAir filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
lDo not twist the element when squeezing
the element.
lLeaving too much of solvent in the ele-
ment may result in poor starting.
4. Inspect:
lAir filter element
Damage ® Replace.
5. Apply:
lFoam-air-filter oil or engine mixing oil
To the element.
NOTE:
Squeeze out the excess oil. Element should
be wet but not dripping.
6. Install:
lAir filter element 1
NOTE:
Align the projection a on the air filter case with
the hole b in the air filter element.
7. Install:
lAir filter case cover
8. Install:
lAir scoop (right)