5-24 ENGINE TOP END
Cylinder Compression Measurement
Use the battery which is fully charged.
Warm up the engine thoroughly.
Stop the engine.
Seat (see Seat Removal in the Frame chapter)
Fuel Tank (see Fuel Tank Removal in the Fuel System
Special Tool - Spark Plug Wrench, Hex 16: 57001-1262
Attach the compression gauge [A] and adapter [B] firmly
into the spark plug hole.
Using the starter motor, turn the engine over with the throt-
tle fully open until the compression gauge stops rising; the
compression is the highest reading obtainable.
Special Tools - Compression Gauge, 20 kgf/cm²: 57001-221
Repeat the measurement for the other cylinders.
Install the spark plugs.
Torque - Spark Plugs: 18 N·m (1.8 kgf·m, 13 ft·lb)
The following table should be consulted if the obtainable compression reading is not within the us-
higher than usable
lower than usable
Compression Gauge Adapter, M10 × 1.0:
980 ∼ 1570 kPa (10.0 ∼ 16.0 kgf/cm²,
142 ∼ 228 psi) @470 r/min (rpm)
Carbon accumulation on piston and in
combustion chamber possibly due to
damaged valve stem oil seal and/or
damaged piston oil rings (This may be
indicated by white exhaust smoke).
Incorrect cylinder head gasket thickness.
Gas leakage around cylinder head
Bad condition of valve seating
Incorrect valve clearance.
Incorrect piston/cylinder clearance
Bad condition of piston ring and/or piston
manuals search engine
Remove the carbon deposits
and replace damaged parts if
Replace the gasket with a standard
Replace damaged gasket and
check cylinder head warp.
Repair if necessary.
Adjust the valve clearance.
Replace the piston and/or cylinder
Inspect the cylinder and
replace/repair the cylinder and/or
piston as necessary.
Replace the piston and/or the