Suzuki AN400 Service Manual page 78

3-32 ENGINE
FINAL SEAT CUT
• If the contact area W is too low or too narrow, use the 45 °
cutter to raise and widen the contact area.
• After the desired seat position and width is achieved, use the
45 ° cutter very lightly to clean up any burrs caused by the
previous cutting operations.
$
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.
NOTE:
After servicing the valve seats, be sure to check the valve clear-
ance after the cylinder head has been reinstalled. (!2-5)
VALVE SEAT SEALING CONDITION INSPECTION
• 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.
(
Always use extreme caution when handling gasoline.
Contact area too low and too
narrow on face of valve
45˚