Valve Seat Inspection And Service - Sym EuroMX 125 Service Manual

6. Cylinder Head/Valve
Hold the cylinder head, and then press out old
valve guide from combustion chamber side.
Tool: Valve guide driver: 5 mm
Caution
• Check if new valve guide is deformation
after pressed it in.
• When pressing in the new valve guide,
cylinder head still have to be kept in
100~150℃.
Adjust the valve guide driver and let valve guide
height is in 13mm.
Press in new valve guide from rocker arm side.
Tool: Valve guide driver: 5 mm
Wait for the cylinder head cooling down to room
temperature, and then correct the new valve
guide with reamer.
Caution
• Using cutting oil when correcting valve
guide with a reamer.
• Turn the reamer in same direction when it
be inserted or rotated.
Correct valve seat, and clean up all metal
residues from cylinder head.
Tool: Valve guide reamer 5 mm

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.
6-10
This chapter Contents
13 mm
(0.15in)
Valve guide reamer
5.0mm
Valve guide driver
5.0mm
Valve seat
width