Yamaha YZ450F(V) Owner's Service Manual page 268

CARBURETOR
EC464511
Float height
1. Measure:
• Float height a
Out of specification → Adjust.
Float height:
8.0 mm (0.31 in)
Measurement and adjustment steps:
• Hold the carburetor in an upside down
position.
NOTE:
• Slowly tilt the carburetor in the opposite
direction, then take the measurement
when the needle valve aligns with the float
arm.
• If the carburetor is level, the weight of the
float will push in the needle valve, resulting
in an incorrect measurement.
• Measure the distance between the mating
surface of the float chamber and top of the
float using a vernier calipers.
NOTE:
The float arm should be resting on the nee-
dle valve, but not compressing the needle
valve.
• If the float height is not within specification,
inspect the valve seat and needle valve.
• If either is worn, replace them both.
• If both are fine, adjust the float height by
bending the float tab b on the float.
• Recheck the float height.
EC464600
Float
1. Inspect:
• Float 1
Damage → Replace.
4 - 14
ENG