Measuring The Compression Pressure - Yamaha 2004 YP400 Service Manual

MEASURING THE COMPRESSION PRESSURE

1
EAS00067
MEASURING THE COMPRESSION
PRESSURE
NOTE:
_
Insufficient compression pressure will result in
a loss of performance.
1. Remove:
• storage box lower plate
Refer to "RIDER SEAT AND STORAGE
BOX".
2. Measure:
• valve clearance
Out of specification → Adjust.
Refer to
CLEARANCE".
3. Start the engine, warm it up for several min-
utes, and then turn it off.
4. Disconnect:
• spark plug cap
5. Remove:
• spark plug
CAUTION:
_
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.
6. Install:
• compression gauge 1
Compression gauge
90890-03081, YU-33223
Adapter (compression gauge)
90890-04082
3 - 20
CHK
ADJ
"ADJUSTING THE VALVE