Yamaha Grizzly 450 2010 Owner's Manual page 104

1. Spark plug cap
3. Remove the spark plug as shown, with the
spark plug wrench included in the owner's tool
kit.
8
1. Spark plug wrench
To check the spark plug
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).
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.
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