Yamaha XVS6501997 Service Manual page 71

COMPRESSION PRESSURE MEASUREMENT
Compression pressure
(with oil applied in the cylinder)
Reading
Higher than
without oil
Same as
without oil
Compression pressure
(at sea level)
Standard:
1,100 kPa (11 kg/cm
Minimum:
1,000 kPa (10 kg/cm
Maximum:
1,200 kPa (12 kg/cm
*****************************************************
Measurement steps:
D Crank the engine with the throttle wide open
until the reading on the compression gauge
stabilizes.
To prevent sparking, ground all spark plug
leads before cranking the engine.
D Repeat the previous steps for the other cylin-
ders.
NOTE:
The difference in compression pressure be-
tween the highest and lowest cylinder compres-
sion readings should not exceed 100 kPa (1
2
kg/cm , 1 bar).
*****************************************************
7. Install:
S Spark plugs
S Spark plug caps
3-15
INSP
ADJ
Diagnosis
Worn or damaged pistons
! Repair.
Possible defective ring(s),
valves, cylinder head gas-
ket or piston ! Repair.
2
, 11 bar)
2
, 10 bar)
2
, 12 bar)
18 Nm (1.8 mSkg)