Valve Stem Replacement - Sym HD2 125 Service Manual

7. CYLINDER HEAD / VALVE
Caution
If clearance between valve stem and valve guide
exceeded service limit, check whether the new
clearance that only replaces new valve guide is
within service limit or not. If so, replace valve
guide.
Correct it with reamer after replacement.
If clearance still exceeds service limit after
replaced valve guide, replace valve stem too.
Caution
It has to correct valve seat when replacing valve
guide.

Valve Stem Replacement

Heat up cylinder head to 100~150 ℃ with heated
plate or toaster.
Caution
Do not let torch heat cylinder head directly.
Otherwise, the cylinder head may be deformed
as heating it.
Wear on a pair of glove to protect your hands
when operating.
Hold the cylinder head, and then press out old
valve guide from combustion chamber side.
Tool: Valve guide driver: 5.0 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 13 mm.
Press in new valve guide from rocker arm side.
Tool: Valve guide driver: 5.0 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: 5.0 mm
7-8
To this chapter contents
℃ .
Valve guide driver
5.0mm
Valve guide reamer 5.0 mm
Valve guide driver
5.0 mm