2001 YAMAHA TTR90 weight

4 - 5
ENG

CARBURETOR
EC464401
Jet needle
1.Inspect:
l
Jet needle
1
Bends/wear ® Replace.
lClip groove
Free play exists/wear ® Replace.
lClip position
Float height
1.Measure:
lFloat height a
Out of specification ® Adjust.
Standard clip position:
No.2 Groove
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 - 14
ENGCAMSHAFT AND ROCKER ARMS
REMOVAL POINTS
Rocker arm shaft
1.Remove:
lRocker arm shafts
NOTE:
Use a slide hammer bolt 1 and weight 2 to
slide out the rocker arm shafts.
Slide hammer set:
YU-1083-A
Slide hammer bolt:
90890-01085
Weight:
90890-01084
INSPECTION
Camshaft
1.Measure:
lCam lobes length a and b
Out of specification ® Replace.
Cam lobes length limit:
Intake:
a 25.328 mm (0.9972 in)
b 20.934 mm (0.8242 in)
Exhaust:
a 25.186 mm (0.9916 in)
b 20.947 mm (0.8247 in)
ASSEMBLY AND INSTALLATION
1.Apply:
lMolybdenum disulfide oil
(onto the camshaft cam lobe)
lEngine oil
(onto the camshaft bearing)
2.Install:
lCamshaft 1

5 - 8
CHAS

FRONT FORK
REMOVAL POINTS
Inner tube
1. Remove:
l
Bolt (damper rod)
NOTE:

While holding the damper rod with the damper
rod holder
1
and T-handle
2
, loosen the bolt
(damper rod).
Damper rod holder:
YM-1300/90890-01294
T-handle:
YM-01326/90890-01326
EC555000
ASSEMBLY AND INSTALLATION
Front fork assembly
1. Install:
l
Oil seal
1

NOTE:

Press the oil seal into the outer tube with fork
seal driver weight
2
and fork seal driver
attachment
3
.
2. Fill:
l
Fork oil
3. After filling up, slowly pump the fork up
and down to distribute the fork oil.
Fork seal driver weight:
YM-33963/90890-01184
Fork seal driver attachment:
90890-01186
Oil quantity:
64 cm
3

(2.26 Imp oz, 2.16 US oz)
Recommended oil:
Fork oil 15W or equivalent