Cylinder Head Inspection - Sym GTS 250 Service Manual

6. Cylinder Head / Valve

Cylinder Head Inspection

Check if spark plug and valve holes are cracked.
Measure cylinder head warp with a straightedge
and thickness gauge.
Service limit: 0.05 mm
Camshaft
Inspect cam lobe height for damaged.
Service Limit:
IN: Replacement when less than 34.860mm
EX: Replacement when less than 34.725mm
Inspect the camshaft bearing for looseness or
wear out. If any damage, replace whole set of
camshaft and bearing.
Rocker Arm
Measure the cam rocker arm I.D., and wear or
damage, oil hole clogged?
Service Limit: Replace when it is less than
12.080 mm.
Rocker Arm Shaft
Measure the active O.D. of the cam rocker arm
shaft and cam rocker arm.
Service Limit: Replace when it is less than
11.936 mm.
Calculate the clearance between the rocker arm
shaft and the rocker arm.
Service Limit: Replace when it is less than 0.10
mm.
6-8
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