Sym SYM series, Manual, Page: 140 / 178

SYM 6. CYLINDER HEAD/VALVE
6-7
After removed valve cotters, release the
compressor and then take out spring retainer,
valve spring and valves.
Caution
Special Service Tool: Valve spring compressor.
Remove valve stem guide seal.
Clean carbon deposits in combustion chamber.
Clean residues and foreign materials on
cylinder head matching surface.
Caution
CYLINDER HEAD INSPECTION
Check if spark plug and valve holes are crack.
Measure cylinder head flat with a
straightedge and flat feeler gauge.
Service limit: 0.05mm
Valve spring free length
Measure the free length of intake and
exhaust valve springs.
Standard
Outer : 35.250 mm
Inner : 32.410 mm
In order to avoid to loosing spring tension,
do not compress the spring too much. Its
length is based on the installation of latch.
Do not damage the matching surface of
cylinder head.
The narrow pitch of the spring shall face to the
combustion chamber.
valve cotters