Compression Measurement - Yamaha XT 600 AC Service Manual

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COMPRESSION PRESSURE MEASUREMENT
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3-15
7. Check:
• Compression pressure
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Checking steps:
.Crank over the engine with the electric starter
(be sure the battery is fully charged) with the
throttle wide-open until the compression
reading on the gauge stabilizes .
AWARNING
When cranking the engine. ground the spark
plug lead to prevent sparking .
• Check reading with specified levels (see
chart) .
Compression pressure (at sea level):
Standard:
1.100 kPa (11 kg/cm2. 156 psi)
Minimum:
900 kpa (9kg/cm 2 • 128 psi)
Maximum:
1.200 kPa (12kg/cm 2 • 171 psi)
.If pressure falls below the minimum level:
1) Squirt a few drops of oil into the affected
cylinder.
2) Measure the compression again .
Compression pressure
(with oil introduced into cylinder)
Reading
Diagnosis
Higher than without Worn or damaged
oil pistons
Defective ring(s).
Same as without oil
valve(s). cylinder
head gasket or
piston is possible.
Inspect cylinder head,
Above maximum valye surfaces, or
level piston crown for
carbon deposits.
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8. Remove :
-Sub tank (fuel)
-Compression gauge (with an adapter)