8. CYLINDER HEAD/VALVES MXU 550EXi /MXU500i
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).
Park Plug Cap
Compression Gauge
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.
To avoid discharging the battery, do not
operate the starter motor for more than
seven seconds.
Compression pressure:
15 kg/cm2 (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
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