Yamaha Fazer, Service Manual

Page: 91 / 213

ENG
INSPECTION AND REPAIRS
4-17
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Lapping steps :
• Apply coarse lapping compound ç to the Valve
Face
• Apply molybdenum disulfide oil to the Valve
Stem.
• Install the Valve into the Cylinder Head.
• Turn the Valve in one Direction using the Valve
lapping tool until the Valve Face and Valve
Seat are evenly polished, then clean off all
compound.
NOTE :
For best lapping results, lightly tap the Valve
seat while rotating the Valve.
• Apply a fine lapping compound è to the Valve
face and repeat the above steps.
NOTE :
Make sure to clean off all compound from the
Valve face and Valve seat after every lapping
operation.
• Apply Mechanic’s blueing dye (Dykem) è to
the Valve face.
• Install the Valve in the Cylinder Head.
• Press the Valve through the Valve Guide and
onto the Valves Seat to make a clear pattern.
• Measure the Valve Seat width é again. If the
Valve Seat width is out of specification, lap the
Valve and Valve Seat.
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WARNING
CAUTION:
Do not let compound enter the gap between the
Valve Stem and the Guide.