Cylinder Compression Test; Cam Chain Adjustment - Sym PA12B Service Manual

Cylinder Compression Test

Warm up engine and turn it off.
Remove spark plug cap and spark plug.
Install compression gauge into the spark plug
hole, full open the throttle, and kick the kick
starter for several times.
Caution:
Rotate the engine until the reading in the
gauge gains no more.
Usually, the highest-pressure reading
will appear in 4~7 seconds.
Compression pressure：12 ±1 Kg/cm²
Check the following items if the pressure
reading is too low:
Incorrect valve clearance.
Valve leaking.
Cylinder head leaking, piston, piston ring
and cylinder worn out.
If the pressure is too high, it means carbon
deposits in combustion chamber or piston
head.

Cam Chain Adjustment

Start the engine, and let the engine idle.
Remove the rubber cap of the adjusting
screw and loosen the lock nut. Turn the
adjusting screw in or out to find a most silent
cam chain setting.
If you want to tighten the chain, turn the
screw counterclockwise, or turn the screw
clockwise to loosen the cam chain. After
finding a best set of cam chain, tighten the
lo ck nut and re-install the rubber cap.
To this chapter contents
Spark plug hole
2. Maintenance Information
Cam-chain adjusting screw
Compression
gauge
Lock nut
2-11