Electrical - Yamaha YZ450FA 2011 Owner's Service Manual

ELECTRICAL

CHECKING THE SPARK PLUG
1. Remove:
• Spark plug
2. Inspect:
• Electrode "1"
Wear/damage → Replace.
• Insulator color "2"
Normal condition is a medium to light tan
color.
Distinctly different color → Check the engine
condition.
An extended run at low speeds causes the in-
sulator to be colored black even if the air-fuel
mixture is normal.
3. Measure:
• Plug gap "a"
Use a wire gauge or thickness gauge.
Out of specification → Regap.
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
4. Clean the plug with a spark plug cleaner if
necessary.
5. Tighten:
• Spark plug
Spark plug:
13 Nm (1.3 m•kg, 9.4 ft•lb)
• Before installing a spark plug, clean the gas-
ket surface and plug surface.
• Finger-tighten "a" the spark plug before torqu-
ing to specification "b".
CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw "1"
2. Attach:
• Timing light
• Digital tachometer
To the ignition coil lead (orange lead "1").
Timing light:
YM-33277-A/90890-03141
3. Adjust:
• Engine idling speed
Refer to "ADJUSTING THE ENGINE
IDLING SPEED" section.
3-37
ELECTRICAL