Checking The Fuel Injector; Checking The Throttle Body - Yamaha 2004 YP400 Service Manual

THROTTLE BODY AND FUEL INJECTOR
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EAS00912

CHECKING THE FUEL INJECTOR

1. Check:
• fuel injector
Damage → Replace.
EAS00913

CHECKING THE THROTTLE BODY

1. Check:
• throttle body
Cracks/damage → Replace the throttle
body.
2. Check:
• piston valve 1
Damage/scratches/wear → Replace.
• piston valve diaphragm 2
Cracks/tears → Replace.
3. Check:
• vacuum chamber cover 1
• piston valve spring 2
Cracks/damage → Replace.
4. Check:
• piston valve movement
Insert the piston valve into the throttle body
and move it up and down.
Tightness → Replace the piston valve.
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