Honda 2004 CRF150F Owner's Manual page 87

Spark Plug
2. Disconnect the spark plug cap.
3. Remove the spark plug with a plug wrench
( ) provided with your motorcycle. 1
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:
0.031 0.035 in (0.80 0.90 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).
78
Servicing Your Honda
3
4
5
7. Tighten the spark plug:
about 1/8-1/4 turn after it seats (if the old
plug is good).
about 1/2 turn after it seats (if installing a
new plug).
Improperly tightened spark plugs can damage
the engine. Too loose, you can burn a piston.
Too tight, you can damage the threads.