Cylinder Head Inspection - Sym Mio 50 Service Manual

6. Cylinder Head / Valve

Cylinder Head Inspection

Cylinder Head
Check if spark plug and valve holes are crack.
Measure cylinder head wrap age 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.
Service limit: 31.5mm
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: (Refer to page 2)
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: 5.03mm
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: (Refer to page 2)
6-10
To this chapter contents
The narrow pitch of the spring shall face to the
5.0mm valve guide reamer
combustion chamber.