2000 YAMAHA TTR90 seat adjustment

SPEC

2 - 5
Cam chain:
Cam chain type/No. of links SILENT CHAIN/84 ----
Cam chain adjustment method Automatic ----
Rocker arm/rocker arm shaft:
Shaft outside diameter 9.981 ~ 9.991 mm
(0.3930 ~ 0.3933 in)9.95 mm
(0.3917 in)
Bearing inside diameter 10.000 ~ 10.015 mm
(0.3937 ~ 0.3943 in)10.03 mm
(0.3949 in)
Valve, valve seat, valve guide:
Valve clearance (cold) IN 0.05 ~ 0.09 mm
(0.0020 ~ 0.0035 in)----
EX 0.08 ~ 0.12 mm
(0.0031 ~ 0.0047 in)----
Valve dimensions:
“A” head diameter IN 22.9 ~ 23.1 mm
(0.9016 ~ 0.9094 in)----
EX 19.9 ~ 20.1 mm
(0.7835 ~ 0.7913 in)----
“B” face width IN 1.19 ~ 2.51 mm
(0.0469 ~ 0.0989 in)----
EX 1.49 ~ 3.07 mm
(0.0587 ~ 0.1209 in)----
“C” seat width IN 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.06 in)
EX 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.06 in)
“D” margin thickness IN 0.5 ~ 0.9 mm
(0.0197 ~ 0.354 in)----
EX 0.8 ~ 1.2 mm
(0.0315 ~ 0.0472 in)----
Stem outside diameter IN 4.475 ~ 4.490 mm
(0.1762 ~ 0.1768 in)4.45 mm
(0.1752 in)
EX 4.460 ~ 4.475 mm
(0.1756 ~ 0.1762 in)4.44 mm
(0.1748 in)
Guide inside diameter IN 4.500 ~ 4.512 mm
(0.1772 ~ 0.1776 in)4.53 mm
(0.1783 in)
EX 4.500 ~ 4.512 mm
(0.1772 ~ 0.1776 in)4.53 mm
(0.1783 in)
Stem-to-guide clearance IN 0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)0.08 mm
(0.003 in)
EX 0.025 ~ 0.052 mm
(0.0010 ~ 0.0020 in)0.10 mm
(0.004 in) Item Standard Limit
Head Diameter
B
Face WidthC
Seat Width
D
Margin ThicknessA

MAINTENANCE SPECIFICATIONS

3 - 7
INSP
ADJ
PILOT AIR SCREW ADJUSTMENT
4. Install:
lGasket
lDrain bolt
New
T R..20 Nm (2.0 m · kg, 14 ft · lb)
5. Fill:
lCrankcase
Oil quantity:
Total amount:
1.0 L (0.88 Imp qt, 1.06 US qt)
Periodic oil change:
0.8 L (0.70 Imp qt, 0.85 US qt)
6. Install:
lDipstick
7. Inspect:
lEngine (for oil leaks)
lOil level
Refer to “ENGINE OIL LEVEL INSPEC-
TION”.
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
lPilot air screw 1
Adjusting steps:
lScrew in the pilot air screw until it is lightly
seated.
lBack out by the specified number of turns.
Pilot air screw:
1-3/4 turns out

4 - 5
ENGCARBURETOR
EC464400
Jet needle
1. Inspect:
lJet needle 1
Bends/wear ® Replace.
lClip position
Standard clip position:
No.2 Groove
EC464511
Float height
1. Measure:
lFloat height a
Out of specification ® Adjust.
Float height:
15.5 ~ 16.5 mm (0.61 ~ 0.65 in)
Measurement and adjustment steps:
lHold the carburetor in an upside down
position.
lMeasure the distance between the mating
surface of the float chamber and top of the
float using a vernier calipers.
lIf the float height is not within specifica-
tion, inspect the valve seat and needle
valve.
lIf either is worn, replace them both.
lIf both are fine, adjust the float height by
bending the float tab 1 on the float.
lRecheck the float height.
NOTE:
lSlowly tilt the carburetor in the opposite
direction, then take the measurement
when the needle valve aligns with the float
arm.
lIf the carburetor is level, the weight of the
float will push in the needle valve, result-
ing in an incorrect measurement.
NOTE:
The float arm should be resting on the nee-
dle valve, but not compressing the needle
valve.

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.