Measuring The Compression Pressure - Yamaha Raptor 90 YFM90RA 2011 Service Manual

MEASURING THE COMPRESSION PRESSURE

EBS00061
MEASURING THE COMPRESSION
PRESSURE
TIP
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
NOTICE
Before removing a 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. Attach:
• compression gauge
Compression gauge
90890-03081
YU-33223
Extension
90890-04082
6. Measure:
• compression pressure
Out of specification → Refer to steps (c)
and (d).
Compression pressure (at sea
level)
Minimum
1,050 kPa/1,000 r/min
(10.5 kg/cm
Standard
1,250 kPa/1,000 r/min
(12.5 kg/cm
Maximum
1,350 kPa/1,000 r/min
(13.5 kg/cm
3 - 15
CHK
ADJ
THE VALVE
2 , 152.3 psi)
2 , 181.3 psi)
2 , 195.8psi)