Yamaha YFM250RX 2008 Service Manual page 277

EBS01034
4. Ignition spark gap
The following procedure applies to all of the
spark plugs.
• Disconnect the spark plug cap from the
spark plug.
• Connect the ignition checker
plug cap as shown.
• Set the main switch to "ON".
• Measure the ignition spark gap
• Crank the engine by pushing the starter
switch and gradually increase the spark gap
until a misfire occurs.
Minimum ignition spark gap
6 mm (0.24 in)
• Is there a spark and is the spark gap within
specification?
NO
and spark
.
1
2
a
YES
The ignition system
is OK.
7-10
IGNITION SYSTEM
EAS00745
5. Spark plug cap resistance
The following procedure applies to all of the
spark plug caps.
• Remove the spark plug cap from the spark
plug lead.
• Connect the pocket tester (Ω × 1k) to the
spark plug cap as shown.
• Measure the spark plug cap resistance.
Spark plug cap resistance
10 kΩ at 20°C (68°F)
• Is the spark plug cap OK?
YES
ELEC
NO
Replace the spark
plug cap.