Cylinder Compression - KYMCO YUP 250 Manual

3
. INSPECTION/ADJUSTMENT

CYLINDER COMPRESSION

Warm up the engine before compression test.
Remove the center cover and spark plug cap.
Remove the spark plug.
Insert a compression gauge.
Open the throttle valves fully and pushes the
starter button to test the compression.
Compression: 16.5±2kg/cm_
If the compression is low, check for the
following:
_Leaky valves
_Valve clearance to small
_Leaking cylinder head gasket
_Worn pistons
_Worn piston/cylinder
If the compression is high, it indicates that
carbon deposits have accumulated on the
combustion chamber and the piston head.
3-7
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YUP 250
Compression Gauge