Yamaha Raptor 90 YFM90RA 2011 Service Manual page 158

CARBURETOR
4. Check:
• piston valve
Damage/scratches/wear
• piston valve diaphragm
Cracks/tears
5. Check:
• vacuum chamber cover
• piston valve spring
Cracks/damage
6 . Check:
• jet needle
• main jet
• Needle jet holder
• Needle jet
• pilot jet
Bends/damage/wear
Obstruction
Blow out the jets with compressed air.
7 . Check:
• fuel hoses
Cracks/damage/wear
Obstruction
Blow out the hoses with compressed air.
8 . Check:
• piston valve movement
Insert the piston valve into the carburetor
body and move it up and down.
Tightness Replace the piston valve.
5 - 5
CARB
Replace.
Replace.
Replace.
Replace.
Clean.
Replace.
Clean.