Honda CRF100F Owner's Manual page 86

1. Clean any dirt from around the spark plug
base.
2. Disconnect the spark plug cap.
3. Remove the spark plug with a plug wrench.
4. Inspect the spark plug electrodes for wear.
The center electrode ( ) should have square
edges. The side electrode ( ) should not be
eroded. The insulator should not be cracked
or chipped.
5. Check the spark plug gap ( ), using a wire-
type feeler gauge. If adjustment is necessary,
bend the side electrode carefully. The gap
should be:
0.024 0.028 in (0.60 0.70 mm)
Make sure the plug washer is in good
condition.
If you have to install a new plug, first check
the gap.
6. With the plug washer attached, thread the
spark plug in by hand (to prevent cross-
threading).
1
2
3
7. Tighten the spark plug:
If the old plug is good:
1/8 turn after it seats.
If installing a new plug, tighten it twice to
prevent loosening:
a) First, tighten the plug:
NGK: 1
DENSO: 3/4
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats.
Improperly tightened spark plugs can damage
the engine. Too loose, you can burn a piston.
Too tight, you can damage the threads.
8. Connect the spark plug cap.
Spark Plug
turn after it seats.
turn after it seats.
Servicing Your Honda
77