Sym Fiddle II 50 SYM Series User Manual

6. CYLINDER HEAD/VALVE SYM
6-8
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: below 0.05mm
Valve spring free length
Measure the free length of intake and
exhaust valve springs.
Standard:
35.250 mm
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→ 4.900mm
EX→ 4.900mm
Valve guide
Caution
Special Service Tool: 5.0mm valve guide
reamer
Measure and record each valve guide inner
diameters.
Service limit: 5.030mm
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→ 0.08mm
EX→ 0.10mm
Before measuring the valve guide, clean
carbon de
p
osits with reamer.
5.0mm valve guide reamer
The narrow pitch of the spring shall face to the
combustion chamber.

Sym Fiddle II 50 SYM Series Specifications

General

Brand	Sym
Model	Fiddle II 50 SYM Series
Category	Motorcycle
Language	English