Cylinder Compression; Cylinder Head Cover - Honda CBR125R Owner's Manual

CYLINDER HEAD/VALVES

CYLINDER COMPRESSION

Warm the engine to normal operating temperature.
Stop the engine.
Remove the spark plug (page 3-9).
Install the compression gauge attachment into the
spark plug hole.
Connect the compression gauge to the attachment.
TOOL:
Compression gauge attachment 07RMJ-MY50100
Turn the ignition switch ON (and engine stop switch
" ": CM and U type).
Shift the transmission into neutral.
Crank the engine with the starter motor.
Open the throttle all the way and crank the engine
To avoid discharging
with the starter motor until the gauge reading stops
the battery, do not
rising.
operate the starter
motor for more
STANDARD:
than 7 seconds.
1,343 kPa (13.7 kgf/cm
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

CYLINDER HEAD COVER

REMOVAL
Remove the middle cowl (page 2-9).
Remove the radiator lower mounting bolt, then
The cylinder head
move the radiator forward.
cover can be
serviced with the
engine installed in
the frame.
8-6
or equivalent com-
mercially available
2 -1
, 195 psi) at 530 min (rpm)
COMPRESSION GAUGE
COMPRESSION GAUGE ATTACHMENT
BOLT RADIATOR