Yamaha XT660R Service Manual page 396

EAS00742
4. Ignition spark gap
• Disconnect the spark plug cap 1 from the
spark plug.
• Connect the ignition checker 2 as shown.
• Set the main switch to "ON".
• Measure the ignition spark gap a.
• Crank the engine by pushing the start
switch and gradually increase the spark
gap until a misfire occurs.
Minimum ignition spark gap
6.0 mm (0.24 in)
• Is there a spark and is the spark gap within
specification?
YES
NO
The ignition system
is OK.
IGNITION SYSTEM
EAS00744
5. Spark plug cap resistance
• 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
10.0 kΩ at 20 °C (68 °F)
• Is the spark plug cap OK?
8 - 14
ELEC
YES
Replace the spark
plug cap.
– +
NO