Yamaha YZF-R1PC Utility Trailer User Manual


 
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CHK
ADJ
MEASURING THE COMPRESSION PRESSURE
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a. Set the main switch to ON.
b. With the throttle wide open, crank the
engine until the reading on the compression
gauge stabilizes.
WARNING
_
To prevent sparking, ground all spark plug
leads before cranking the engine.
NOTE:
_
The difference in compression pressure
between cylinders should not exceed 100 kPa
(1 kg/cm
2
, 1 bar).
c. If the compression pressure is above the
maximum specification, check the cylinder
head, valve surfaces and piston crown for
carbon deposits.
Carbon deposits Eliminate.
d. If the compression pressure is below the
minimum specification, pour a teaspoonful
of engine oil into the spark plug bore and
measure again.
Refer to the following table.
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Compression pressure
(at sea level)
Minimum
1,350 kPa
(13.5 kg/cm
2
, 192 psi)
Standard
1,450 kPa
(14.5 kg/cm
2
, 206 psi)
Maximum
1,500 kPa
(15.0 kg/cm
2
, 213 psi)
Compression pressure
(with oil applied into the cylinder)
Reading Diagnosis
Higher than with-
out oil
Piston ring(s) wear
or damage
Repair.
Same as without
oil
Piston, valves, cyl-
inder head gasket
or piston possibly
defective
Repair.