Valve Stem; Valve Guide - SANYANG INDUSTRY CO. SYM Service Manual

SYM

Valve stem

Check if valve stems are bend, crack or burn.
Check the operation condition of valve stem
in valve guide, and measure & record the
valve stem outer diameter.
Service Limit: IN¡ ÷
EX¡ ÷

Valve guide

Caution
Before measuring the valve guide, clean
carbon deposits with reamer.
Special Service Tool: 5.0mm valve guide
reamer
Measure and record each valve guide inner
diameters.
Service limit: 5.300mm
The difference that the inner diameter of
valve guide deducts the outer diameter of
valve stem is the clearance between the
valve stem and valve guide.
Service Limit: IN¡ ÷
EX¡ ÷
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 must correct valve seat when replacing
valve guide.
Valve guide replacement
Heat up cylinder head to 100~150 ¢ J 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.
4.900mm
4.900mm
0.08mm
0.10mm
6. CYLINDER HEAD/VALVE
5.0mm valve guide reamer
Valve guide driver
5.0mm
6-9