Compression Check: Testing and Inspection

Compression

INSPECTION

CAUTION:
After warming-up, engine becomes very hot. Be careful not to burn yourself during measurement.

1) Remove the collector cover.
2) After warming-up the engine, turn the ignition switch to OFF.
3) Make sure that the battery is fully charged.
4) Release the fuel pressure.
5) Remove all spark plugs.
6) Fully open the throttle valve.
7) Check the starter motor for satisfactory performance and operation.
8) Secure the compression gauge tightly against the spark plug hole.

NOTE:
When using a screw-in type compression gauge, the screw should be less than 18 mm (0.71 in) long.

9) Crank the engine by the starter motor, and read the maximum value on the gauge when the needle of gauge is steady.

NOTE:
^ Perform at least two measurements per cylinder, and make sure that the values are correct.
^ If the compression pressure is out of standard, check or adjust the pistons, valves and cylinders.

Compression (350 rpm and fully open throttle):
Standard
1,275 - 1,471 kPa (13.0 - 15.0 kgf/cm2, 185 - 213 psi)
Limit
1,128 kPa (11.5 kgf/cm2, 164 psi)
Difference between cylinders
49 kPa (0.5 kgf/cm2, 7 psi) or less

10) After inspection, install the related parts in the reverse order of removal.