Yamaha XT250X - Measuring the Compression Pressure

ENGINE
3-9
2. Connect:
●
Timing light “1”
● Digital tachometer
3. Check:
●
Ignition timing
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a. Start the engine, warm it up to the specified
oil temperature, then adjust to the standard
idling speed.
b. Check the firing range as shown.
Out of the firing range → Check the ignition
system
NOTE:
The ignition timing is not adjustable.
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4. Remove:
● Digital tachometer
● Timing light
5. Install:
● Timing mark accessing screw
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
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
4. Remove:
● Spark plug
CAUTION:
ECA13340
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”
Timing light
90890-03141
Inductive clamp timing light
YU-03141
Digital tachometer
90890-06760
YU-39951-B
Engine idling speed
1300–1500 r/min
1