Compression Pressure Measurement - Yamaha Fazer Service Manual

COMPRESSION PRESSURE MEASUREMENT

COMPRESSION PRESSURE
(With oil applied into cylinder)
Reading
Higher than without oil
Same as without oil
Possible defective
ring(s),Valves,Cylinder
head Gasket or Pis-
ton Ÿ Repair.
COMPRESSION PRESSURE MEASUREMENT
¿ NOTE :
Insufficient compression pressure will result in
performance loss.
Diagnosis
Worn or damaged
piston
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Measurement steps:
• Crank the Engine with the Throttle wide open
Before cranking the engine, ground Spark
Plug leads to prevent sparking
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3-13
1. Check :
• Valve clearance
Out of specification Ÿ Adjust.
Refer to "VALVE
ADJUSTMENT" section. Page no 3-6
2. Start the Engine and let it warm up for sev-
eral minutes.
3. Turn off the engine.
4. Remove :
• Spark Plug
5. Attach:
• Compression gauge ¿
Compression Gauge :
6. Measure :
• Compression pressure
If it exceeds the maximum pressure allowed
” Inspect the Cylinder Head, Valve surfaces
and Piston Crown for carbon deposits.
If it is below the minimum pressure ”
Squirt a few drops of oil into the affected
cylinder and measure again.
Follow the table
Compression pressure :
(at sea level)
Standard : 1200 kPa (12 Kg/cm²)
Minimum : 1040 kPa (10.4 Kg/cm²)
until the reading on the compression gauge
stabilizes.
WARNING
7. Install :
• Spark plug
INSP
ADJ
CLEARANCE