Suzuki GN125F, Service Manual

Page: 29 / 148

COMPRESSION PRESSURE
A low compression pressure may indicate any of the following malfunctions:
Excessively worn cylinder wall.
Worn piston or piston rings.
Piston rings stuck in the grooves.
Poor seating contact of valves.
Defective cylinder head gasket.
NOTE:
Before testing the engine for compression pressure, make sure that the cylinder head nuts
and bolts are tightened to specified torque values and valves clearance are properly adjusted.
Have the engine warmed up by idling before testing it.
Ensure that the battery is fully charged.
*
*
Compression gauge
09915-64512
Adapter
09915-63310
①
②
Compression pressure
Standard
Limit
8 kg/cm
2
10-14 kg/cm
2
When the compression pressure noted is down to or below the limit indicated above, the engine must be
disassembled, inspected and repaired as required.
2
1
1
2-17
Cylinder compression is an indicator of its inner state. The necessity of repair depends on the result of
inspection. The record of your authorized maintenance dealer should include compression pressure
readings obtained in every maintenance.
Remove related parts and inspect compression pressure in the following process:
Support the motorcycle with the main stand;
Remove spark plug;
Fit pressure gauge and adapter to the spark plug
hole, pay attention to connector tightening;
Turn throttle to full opening;
Electrically start the motorcycle, take the maximum
reading in the recording as cylinder compression pressure.
① ②
*
2
2-17
Inspect initial 1 000 km and every 5 000 km