Yamaha Rhino 450 YXR45FAV Service Manual page 88

MEASURING THE COMPRESSION PRESSURE
1
4. Remove:
• spark plug
5. Attach:
• adapter
• compression gauge 1
Engine compression tester
P/N. YU-33223
Compression gauge
P/N. 90890-03081
Extension
P/N. 90890-04082
6. Measure:
• compression pressure
Above the maximum pressure:
Check 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.
Refer to the table below.
Compression pressure
(with oil introduced into cylinder)
Reading
Higher than
without oil
Same as with-
out oil
Compression pressure
(at sea level)
Standard:
1,270 kPa
(12.70 kg/cm
at 700 r/min
Minimum:
1,105 kPa
(11.05 kg/cm
at 700 r/min
Maximum:
1,422 kPa
(14.22 kg/cm
at 700 r/min
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Crank over the engine with the electric starter
(be sure the battery is fully charged) with the
throttle wide-open until the compression read-
ing on the gauge stabilizes.
3 - 12
CHK
ADJ
Diagnosis
Worn or damaged piston
ring(s)
Defective piston ring(s),
valve(s), cylinder head
gasket or piston is pos-
sible.
2
, 180.6 psi)
2
, 157.1 psi)
2
, 202.2 psi)
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