Yamaha VMX12 2001 Service Manual page 404

EAS00743
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 1 as shown.
2 Spark plug cap
• 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 mm
• Is there a spark and is the spark gap within
specification?
NO
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.
YES
The ignition system
is OK.
IGNITION SYSTEM
Spark plug cap resistance
10 kΩ at 20 °C
• Is the spark plug cap OK?
EAS00747
6. Ignition coil resistance
The following procedure applies to all of the
ignition coils.
• Disconnect the ignition coil leads from the
wire harness.
• Connect the pocket tester (Ω × 1) to the
ignition coil as shown.
Positive tester probe → red/white 1
Negative tester probe → orange 2
• Measure the primary coil resistance.
Primary coil resistance
2.43 ~ 2.97 Ω at 20 °C
• Connect the pocket tester (Ω × 1k) to the
ignition coil as shown.
Negative tester probe → red/white 1
Positive tester probe → spark plug lead 2
8 - 12
ELEC
YES
Replace the spark
plug cap.
– +
NO