Measuring The Compression Pressure - Yamaha XT250X 2008 Service Manual

2. Connect:
Timing light "1"
G
Digital tachometer
G
Timing light
90890-03141
Inductive clamp timing light
YU-03141
Digital tachometer
90890-06760
YU-39951-B
1
3. Check:
Ignition timing
G
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
a. Start the engine, warm it up to the specified
oil temperature, then adjust to the standard
idling speed.
Engine idling speed
1300–1500 r/min
b. Check the firing range as shown.
Out of the firing range → Check the ignition
system
All manuals and user guides at all-guides.com
3-9
NOTE:
The ignition timing is not adjustable.
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4. Remove:
Digital tachometer
G
Timing light
G
5. Install:
Timing mark accessing screw
G
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. Measure:
Valve clearance
G
Out of specification → Adjust.
Refer to "ADJUSTING THE VALVE CLEAR-
ANCE" on page 3-5.
2. Start the engine, warm it up for several min-
utes, and then turn it off.
3. Disconnect:
Spark plug cap
G
4. 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.
5. Install:
Compression gauge "1"
G
ENGINE