Checking The Spark Plug - Yamaha YFM50RY Owner's Manual

EBU23211

Checking the spark plug

The spark plug is an important engine component,
which is easy to check. Since heat and deposits
will cause any spark plug to slowly erode, the spark
plug should be removed and checked in accor-
dance with the periodic maintenance and lubrica-
tion chart. In addition, the condition of the spark
plug can reveal the condition of the engine.
To remove the spark plug
1. Remove the spark plug cap.
1. Spark plug cap
2. Remove the spark plug as shown, with the
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1. Spark plug wrench
To check the spark plug
TIP
If the spark plug shows a distinctly different color,
the engine could be operating improperly. Do not
attempt to diagnose such problems yourself. In-
stead, have a Yamaha dealer check the ATV.
8-8
spark plug wrench included in the owner's tool
kit.
1. Check that the porcelain insulator around the
center electrode of the spark plug is a medi-
um-to-light tan (the ideal color when the ATV
is ridden normally).
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