Yamaha XJR1300(L) 99 Service Manual page 73

MEASURING THE COMPRESSION PRESSURE
3. Disconnect:
S spark plug cap
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
S adapter 2
Compression gauge
90890-03081
Adapter
90890-04082
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 into cylinder)
Reading Diagnosis
Higher than Piston wear or damage
! Repair.
without oil
Piston ring(-s), valves, cyl-
inder head gasket
Same as or piston possibly defec-
tive ! Repair.
without oil
Compression pressure (at
sea level)
Compression pressure (at sea lev-
el):
Standard:
1,050 kPa (10.5 kg/cm
10.5 bar)/400 r/min.
Minimum:
900 kPa (9.0 kg/cm
9.0 bar)/400 r/min.
Maximum:
1,200 kPa (12.0 kg/cm
12.0 bar)/400 r/min.
3-15
CHK
ADJ
2
,
2
,
2
,