ENGINE 3-39
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, re-cut 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 valve clear-
ance after the cylinder head has been reinstalled. (2-7)
45˚
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.
The titanium valves are coated with an oxidized mem-
brane treatment to resist wear but the membrane tend
to be removed if lapped after valve seat servicing.
SAMPLE
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