Honda FE500 Owner's Manual page 49

4. Check that the spark plug washer is in good condition and thread the
spark plug in by hand to prevent cross-threading.
SPARK PLUG WRENCH
5. After the spark plug is seated, tighten with a spark plug wrench to
compress the washer.
After seating it by hand, tighten a new spark plug 1/2 turn with the
wrench to compress the washer. If you are reusing a plug, it should
only take 1/8 1/4 turn.
The spark plug must be securely tightened. An improperly tightened
plug can become very hot and possibly damage the engine.
Never use a spark plug with an improper heat range.
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