Valve Seat Inspection And Service - Sym Mio 50 Service Manual

6. Cylinder Head / Valve

Valve Seat Inspection and Service

Clean up all carbon deposits onto intake and
exhaust valves.
Apply with emery slightly onto valve contact face.
Grind valve seat with a rubber hose or other
manual grinding tool.
Caution
Do not let emery enter into between valve
stem and valve guide.
Clean up the emery after corrected, and
apply with red paint onto contact faces of
valve and valve seat.
Remove the valve and check its contact face.
Caution
Replace the valve with new one if valve seal
is roughness, wear out, or incomplete
contacted with valve seat.
If the valve and the valve seat still can not be
matched sealing after grinded, replace it with
new one.
Valve seat inspection
If the valve seat is too width, narrow or rough,
corrects it.
Valve seat width
Service limit: 1.6mm
Check the contact condition of valve seat.
Valve seat grinding
The worn valve seat has to be grinded with valve
seat chamfer cutter.
Refer to operation manual of the valve seat
chamfer cutter.
Use 45° valve seat chamfer cutter to cut any rough
or uneven surface from valve seat.
Caution
After valve guide had been replaced, it has to
be grinded with 45° valve seal chamfer cutter
to correct its seat face.
Use 32° cutter to cut a quarter upper parts out.
6-12
To this chapter contents
Valve seat width
Roughness
45°
Old valve seat width
32°