Ignition System; Cylinder Compression Pressure - Sym HD2 125 Service Manual

2. MAINTENANCE INFORMATION

Ignition System

Caution
Transistor ignition system is set by
manufacturer so it can not be adjusted.
Ignition timing check procedure is for checking
whether ECU function is in normal or not.
Remove right side cover.
Remove ignition timing hole cap located in front
upper side of engine right cover.
Connect tachometer and ignition lamp.
Start engine.
As engine in idle speed: 1600 rpm, aim at the
mark "F" with the ignition lamp. Then, it is means
that ignition timing is correct.
Increase engine speed to 6000 rpm to check
ignition advance degree. If indent is located within
the ignition advance degrees, it is means that the
ignition advance degree is in normal.
If ignition timing is incorrect, check ECU set, pulse
rotor and pulse generator. Replace it if
malfunction of these parts is found.

Cylinder Compression Pressure

Warm up engine.
Turn off the engine.
Remove the trunk.
Remove the central cover.
Remove spark plug cap and spark plug.
Install compression gauge.
Full open the throttle valve, and rotate the engine
by means of starter motor.
Caution
Rotate the engine until the reading in the gauge
no more increasing.
Usually, the highest pressure reading will be
obtained in 4~7 seconds.
Compression pressure: 12 ± 2 Kg/cm²
Check following items if the pressure 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.
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