Suzuki DR 125 Service Manual page 62

3-26 ENGINE
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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. (!2-7)
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.
'
Always use extreme caution when handling gasoline.
VALVE STEM END CONDITION
Inspect the valve stem end face for pitting and wear. If pitting or
wear is present, resurface the valve stem end. Make sure that
the length A is not less than 2.5 mm (0.10 in). If this length
becomes less than 2.5 mm (0.10 in), replace the valve.
$ Valve stem end length
Service Limit: 2.5 mm (0.10 in)
VALVE SPRINGS
Check the valve springs for proper strength by measuring their
free length and also the force required to compress them. If the
spring length is less than the service limit or if the force required
to compress the spring does not fall within the specified range,
replace the spring.
$ Valve spring free length (IN. & EX.)
Service Limit INNER : 36.0 mm (1.42 in)
OUTER: 39.3 mm (1.55 in)
& 09900-20101: Venier calipers
45˚