Yamaha XVZ13TF 1999 Service Manual page 101

MEASURING THE COMPRESSION PRESSURE
4. Remove:
S spark plug
CAUTION:
Before removing the spark plugs, use com-
pressed air to blow away any dirt accumu-
lated in the spark plug wells to prevent it
from falling into the cylinders.
5. Install:
S compression gauge 1
Compression gauge
YU-33223, 90890-03081
6. Measure:
S compression pressure
Above the maximum pressure ! Inspect the
cylinder head, valve surfaces, and piston
crown for carbon deposits.
Below the minimum pressure ! Squirt a few
drops of oil into the affected cylinder and
measure again.
S Refer to the following table.
Compression pressure
(with oil applied in the cylinder)
Reading
Higher than
without oil
Same as
without oil
Compression pressure (at sea
level)
Standard:
1,520 kPa (15,2 kg/cm
15.2 bar)
Minimum:
1,300 kPa (13,0 kg/cm
13.0 bar)
Maximum:
1,700 kPa (17,0 kg/cm
17.0 bar)
3-20
CHK
ADJ
Diagnosis
Piston wear or damage !
Repair.
Piston ring(-s), valves,
cylinder head gasket or
piston possibly defective
! Repair.
2
2
2
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