Yamaha 5TE-F8197-10, LIT-11616-16-02 service manual Measuring the Compression Pressure

MEASURING THE COMPRESSION PRESSURE

CHK ADJ

7.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	Diagnosis
Higher than	Worn or damaged pistons
without oil
Same as	Defective ring(s), valves,
	cylinder head gasket or
without oil
	piston is possible.

Compression pressure (at sea level):

Standard:

1,400 kPa (14 kg/cm2, 203 psi) Minimum:

1,218 kPa (12.2 kg/cm2, 177 psi) Maximum:

1,568 kPa (15.7 kg/cm2, 227 psi)

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Measurement 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.

WARNING

When cranking the engine, ground the spark plug lead to prevent sparking.

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8.Install:

● Spark plug	T.R.	18 Nm (1.8 m • kg, 13 ft • lb)
9.Remove:

●Fuel tank side panel (right)

●Seat

Refer to “SEAT, CARRIERS, FENDERS AND FUEL TANK”.

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