Yamaha VMX12 2001 Service Manual page 267

CARBURETORS
8. Check:
• vacuum chamber cover 1
• piston valve spring 2
• jet needle holder 3
• jet needle spring 4
Cracks/damage → Replace.
9. Check:
• jet needle kit 1
• needle jet 2
• main jet 3
• pilot jet 4
• pilot screw assembly 5
• pilot air jet No. 1 6
• pilot air jet No. 2 7
• starter plunger assembly 8
Bends/damage/wear → Replace.
Obstruction → Clean.
Blow out the jets with compressed air.
10.Check:
• piston valve movement
Insert the piston valve into the carburetor
body and move it up and down.
Tightness → Replace the piston valve.
11.Check:
• fuel feed hoses
• fuel hoses
Cracks/damage/wear → Replace.
Obstruction → Clean.
Blow out the hoses with compressed air.
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CARB