height adjustment YAMAHA TTR90 2000 Owners Manual

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.