Sym Joyride 125 Service Manual page 135

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
13 mm
Valve guide reamer 5.0 mm
Valve guide driver
5.0mm
Valve guide driver
5.0 mm