Measuring The Compression Pressure - Yamaha XT660R Service Manual

MEASURING THE COMPRESSION PRESSURE

1
CHECKING THE IGNITION TIMING/
2
3 - 21
4. Detach:
• timing light
5. Install:
• timing mark accessing screw
EAS00067
MEASURING THE COMPRESSION
PRESSURE
NOTE:
_
Insufficient compression pressure will result in
a loss of performance.
1. Measure:
• valve clearance
Out of specification → Adjust.
Refer to "ADJUSTING
CLEARANCE".
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
CAUTION:
_
Before removing the spark plug, blow away
any dirt accumulated in the spark plug well
with compressed air to prevent it from fall-
ing into the cylinder.
5. Install:
• compression gauge 1
• adaptor (compression gauge) 2
Compression gauge
90890-03081
Adaptor (compression gauge)
90890-04082
CHK
ADJ
THE VALVE