KYMCO MXU 500 - Cylinder Compression Test

8. CYLINDER HEAD/VALVES
8-4
MXU 500
CYLINDER COMPRESSION TEST
Warm up the engine to normal operating
temperature.
Stop the engine and remove the spark plug
cap and remove the spark plug (refer to the
“SPARK PLUG” section in the chapter 3).
Install a compression gauge into the spark
plug hole.
Open the throttle all the way and crank the
engine with the starter motor until the gauge
reading stops rising.
The maximum reading is usually reached 4 –
7 seconds.
Compression pressure:
15 kg/cm
2
(1500 kPa, 213 psi)
Low compression can be caused by:
 Blown cylinder head gasket
 Improper valve adjustment
 Valve leakage
 Worn piston ring or cylinder
High compression can be caused by:
 Carbon deposits in combustion chamber or
on piston head
Park Plug Cap
Compression Gauge
To avoid discharging the battery, do not
operate the starter motor for more than
seven seconds.
＊