Measuring The Compression Pressure - Yamaha FZS600'98 Service Manual

MEASURING THE COMPRESSION PRESSURE

EB303060
MEASURING THE COMPRESSION
PRESSURE
The following procedure applies to all of the cyl-
inders.
NOTE:
Insufficient compression pressure will result
in a loss of performance.
1. Check:
S valve clearance
Out of specification ! Adjust.
Refer to "ADJUSTING THE VALVE
CLEARANCE".
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Disconnect:
S spark plug cap
4. Remove:
S spark plug
CAUTION:
Before removing the spark plugs, use
compressed air to blow away any dirt ac-
cumulated in the spark plug wells to pre-
vent it from falling into the cylinders.
5. Install:
S compression gauge 1
Compression gauge
90890-03081
6. Measure:
S compression pressure
Above the maximum pressure ! Inspect
the cylinder head, valve surfaces, and pis-
ton crown for carbon deposits.
Below the minimum pressure ! Squirt a
few measure again.
S Refer to the following table.
Compression pressure
(with oil applied into the cylinder)
Reading
Higher than
without oil
Same as
without oil
3-17
CHK
ADJ
Diagnosis
Piston wear or
damage ! Repair.
Piston ring(-s),
valves cylinder
head gasket or
piston possibly
defective ! Repair.