Electrical - Yamaha 2011 YZ250FA 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.
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
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.
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ELECTRICAL