3-26 ENGINE
FINAL SEAT CUT
• If the contact area is too low or too narrow, use the 60° cutter
to raise and widen the contact area. If the contact area is too
high or too wide, use the 15° or 30° cutter to lower and narrow
it to the correct width.
• After the desired seat position and width is achieved, use the
60° cutter very lightly to clean up any burrs caused by the pre-
vious cutting operations.
"
NOTE:
After servicing the valve seats, be sure to check the tappet
clearance after the cylinder head has been installed. (!2-5 to
2-9)
VALVE SEAT SEALING CONDITION INSPECTION
With the valve and valve spring assembled, pour a small quan-
tity of gasoline into the intake or exhaust port.
Check that no gasoline leaks through the valve seat. If leakage
is found, correct the sealing surface.
'
Contact area too low and
too narrow on face of valve
DO NOT use a lapping compound after the final cut is
made. The finished valve seat should have a velvety
smooth finish but not a highly polished or shiny one.
This will provide a soft surface for the final seating of
the valve which will occur during the first few seconds
of engine operation.
Gasoline is highly flammable and explosive.
Keep heat, sparks, and flames away from gasoline.
60˚
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