Yamaha YBR250 2007 Service Manual page 320

4. Ignition spark gap
• Disconnect the spark plug cap 1 from the
spark plug.
• Connect the spark dynamic tester 2 as
shown.
• Set the main switch to "ON".
• Measure the ignition spark gap a.
• Crank the engine by pushing the starter
switch and gradually increase the spark
gap until a misfire occurs.
Minimum ignition spark gap
6.0 mm (0,024 in)
• Is there a spark and is the spark gap within
specification?
YES NO
The ignition system
is OK.
IGNITION SYSTEM
5. Spark plug cap resistance
• Remove the spark plug cap from lead.
• Connect the pocket tester to the spark
plug cap, as shown.
• Measure the spark plug cap resistance.
Spark plug cap resistance
5.0 kΩ at 20°C (68°F)
• Is the spark plug cap OK?
7-10
ELEC
YES
Replace the spark
plug cap.
NO