Measuring The Compression Pressure - Yamaha 2007 XP500 Service Manual

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a. Start the engine, warm it up for several min-
utes, and then let it run at the specified en-
gine idling speed.
Engine idling speed
1100–1300 r/min
b. Check that the stationary pointer "a" is within
the firing rang "b" on the A.C. magneto.
Incorrect firing range → Check the ignition
system.
NOTE:
The ignition timing is not adjustable.
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5. Install:
Timing plug
G
Timing plug
8 Nm (0.8 m•kg, 5.8 ft•lb)
6. Install:
Left footrest board
G
Side cover (left and right)
G
Center cover
G
Refer to "GENERAL CHASSIS" on page 4-1.
EAS20710
MEASURING THE COMPRESSION
PRESSURE
The following procedure applies to all of the cyl-
inders.
NOTE:
Insufficient compression pressure will result in a
loss of performance.
1. Remove:
Footrest board (left and right)
G
Inner fender
G
Refer to "GENERAL CHASSIS" on page 4-1.
2. Measure:
Valve clearance
G
Out of specification → Adjust.
a
b
3-11
Refer to "ADJUSTING THE VALVE CLEAR-
ANCE" on page 3-3.
3. Start the engine, warm it up for several min-
utes, and then turn it off.
4. Disconnect:
Spark plug cap
G
5. Remove:
Spark plug
G
ECA13340
CAUTION:
Before removing the spark plugs, use com-
pressed air to blow away any dirt accumulat-
ed in the spark plug wells to prevent it from
falling into the cylinders.
6. Install:
Compression gauge "1"
G
Compression gauge
90890-03081
Engine compression tester
YU-33223
Extension
90890-04082
7. Measure:
Compression pressure
G
Out of specification → Refer to steps (c) and
(d).
Standard compression pressure
(at sea level)
1400 kPa/360 r/min (199.1 psi/
360 r/min) (14.0 kgf/cm
min)
Maximum compression pressure
1570 kPa/360 r/min (223.3 psi/
360 r/min) (15.7 kgf/cm
min)
Minimum compression pressure
1200 kPa/360 r/min (170.7 psi/
360 r/min) (12.0 kgf/cm
min)
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a. Set the main switch to "ON".
ENGINE
1
2
/360 r/
2
/360 r/
2
/360 r/