Yamaha YZ450FA 2011 Owner's Service Manual page 268

CHECKING THE IGNITION COIL
1. Remove the ignition coil cap.
2. Inspect:
• Primary coil resistance
Out of specification → Replace.
Tester (+) lead → Orange lead "1"
Tester (-) lead → Red lead "2"
Primary coil re-
sistance
3.57–4.83 Ω at 20
°C (68 °F)
3. Inspect:
• Secondary coil resistance
Out of specification → Replace.
Tester (+) lead → Orange lead "1"
Tester (-) lead → Spark plug terminal "2"
Secondary coil
resistance
10.71–14.49 kΩ
at 20 °C (68 °F)
Disconnect the spark plug cap before measur-
ing the secondary coil resistance.
Tester selector
position
Ω × 1
Tester selector
position
kΩ × 1
7-6
IGNITION SYSTEM
CHECKING THE AC MAGNETO
1. Inspect:
• Crankshaft position sensor resistance
Out of specification → Replace.
Tester (+) lead → Gray lead "1"
Tester (-) lead → Black lead "2"
Crankshaft posi-
tion sensor resis-
tance
248–372 Ω at 20
°C (68 °F)
2. Inspect:
• Stator coil resistance
Out of specification → Replace.
Tester (+) lead → White lead "1"
Tester (-) lead → White lead "2"
Stator coil resis-
tance
0.60–0.90 Ω at
20 °C (68 °F)
Tester selector
position
Ω × 100
Gy B
Tester selector
position
Ω × 10
W2 W1