3-10
MEASURING THE COMPRESSION PRESSURE
CHK
ADJ
NOTE:
CAUTION:
EAS00067
MEASURING THE COMPRESSIONPRES-
SURE
Insufficient compression pressure will result in a
loss of performance.
1. Check:
valve clearance
Out of specification
Adjust
Refer to “ADJUSTING THE VALVE CLEAR-
ANCE ”.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Disconnect:
spark plug cap
4. Remove:
spark plug
Before removing the spark plug, use com-
pressed air to blow away any dirt accumu-
lated in the spark plug well to prevent it from
falling into the cylinder.
5. Install:
compression gauge
1
Compression gauge
1
90890-03081
Adapter
2
90890-04082
6. Measure:
compression pressure
Above the maximum pressure
Inspect the
cylinder head, valve surfaces, and piston
crown for carbon deposits.
Below the minimum pressure
Squirt a few
drops of oil into the cylinder and measure
again.
Refer to the following table.
Compression pressure
(with oil applied into cylinder)
Reading
Diagnosis
Higher than
without oil
Piston wear or damage
Repair.
Same as
without oil
Piston ring(-s), valves,
cylinder head gasket or
piston possibly defec-
tive
Repair.
Summary of Contents for TW125 1999
Page 1: ......
Page 2: ......
Page 8: ......
Page 9: ...GEN INFO 1 ...
Page 11: ......
Page 19: ...GEN INFO ...
Page 20: ...SPEC 2 ...
Page 22: ......
Page 47: ...CHK ADJ 3 ...
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Page 89: ...CHK ADJ ...
Page 90: ...ENG 4 ...
Page 94: ......
Page 162: ...ENG ...
Page 163: ...CARB 5 ...
Page 165: ......
Page 174: ...CHAS 6 ...
Page 236: ...CHAS ...
Page 237: ...ELEC 7 ...
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Page 274: ...TRBL SHTG 8 ...
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Page 282: ...TRBL SHTG ...