Valve Lapping - Yamaha EF3000iSE Service Manual

6. Remove the carbon deposits on the valve
face a and valve seat.
• Valve face contact seat width b
• Valve margin thickness c
Apply a small amount of coarse
Mechanic's blueing dye (Dykem) to the
valve seat.
Press the valve through the valve guide
and onto the valve seat to make a clear
impression.
• Valve margin thickness
Out of specification → Replace.
• Valve face contact width
Out of specification → Replace.
Valve seat width:
Valve margin thickness:
SVU3270

VALVE LAPPING

1. Apply a coarse lapping compound evenly
on the valve face. Lap the valve by tap-
ping and rotating the valve lapper 1
clockwise and counterclockwise.
2. Clean off all of the lapping compound
from the valve face and valve seat. Apply
fine lapping compound on the valve face
and lap the valve as in step 1.
SVU3270J
3. If the contact width on the valve face
shines white along the entire face, apply
Mechanic's blueing dye (Dykem) to make
sure that there are traces of even contact
in the center of the valve face.
CAUTION:
Do not let the lapping compound enter the
gap between the valve stem and the valve
guide.
NOTE:
After every lapping procedure, clean off the
compound from the valve face and valve seat.
3-32
ENG
VALVE
0.9 ~ 1.1 mm (0.0354 ~ 0.0433 in)
0.3 mm (0.012 in)