3-32 ENGINE
BOTTOM NARROWING CUT
• If the contact area
W is too wide or too low, use the 60° cutter
to narrow and raise the contact area.
FINAL SEAT CUT
• If the contact area
W is too low or too narrow, use the 45° cut-
ter to raise and widen the contact area.
NOTE:
After cutting the 15°, 30° and 60° angles, it is possible that the
valve seat (45°) is too narrow. If so, recut the valve seat to the
correct width.
• After the desired seat position and width is achieved, use the
45° 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 reinstalled. (2-9)
• Clean and assemble the head and valve components. Fill the
intake and exhaust ports with gasoline to check for leaks.
• If any leaks occur, inspect the valve seat and face for burrs or
other things that could prevent the valve from sealing.
"
60˚
Too low or too narrow
contact surface on valve
Do not use 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 fin-
ish. This will provide a soft surface for the final seat-
ing of the valve which will occur during the first few
seconds of engine operation.
45˚
Always use extreme caution when handling gasoline.
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