Suzuki DF 40 Service Manual page 178

6-35 POWER UNIT
NOTE:
Clean and assemble cylinder head and valve components.
Fill intake and exhaust ports with solvent to check for leaks be-
tween valve seat and valve.
If any leaks occur , inspect valve seat and face for burrs or other
things that could prevent valve from sealing.
VALVE GUIDE REPLACEMENT
Be careful not to damage cylinder head when replac-
ing valve guide.
(1) Using valve guide remover, drive valve guide out from com-
bustion chamber side towards valve spring side.
09916-44310 : Valve guide remover
NOTE:
Do not reuse valve guide once it has been removed.
Always use a new valve guide (oversize) when assembling.
(2) Ream valve guide hole with f10.5 mm reamer to true hole
and remove burrs.
09916-37320 : Valve guide reamer (f f f f f 10.5mm)
09916-34542 : Reamer handle
NOTE:
Turn reamer clockwise, never counterclockwise.