Cylinder Compression Test; Cylinder Head Cover Removal - Honda SH125 Manual

CYLINDER HEADIVALVES
CYLINDER COMPRESSION TEST
To avoid discharging
the battery, do not
operate the starter
motor for more
than 7 seconds.
Remove the maintenance lid (page 2-4).
Warm up the engine to normal operating tempera-
ture.
Stop the engine and remove the spark plug cap and
spark plug (page 3-6).
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
within 4
-
7 seconds.
COMPRESSION PRESSURE:
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 the combustion chamber or
o n the piston head
1,373 kPa (14.0 kg/cm2, 199 psi) at 600 min-' (rpm)
CYLINDER HEAD COVER REMOVAL
Remove the following:
-
frame body cover (page 2-5)
-
pulse secondary air injection (PAIR) check valve
(page 5-51)
Disconnect the crankcase breather hose.
Remove the two bolts and cylinder head cover.
Remove the rubber seal.
Remove the O-ring and joint collar.
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