CRF150F
4. Visually inspect the spark plug electrodes for
wear. The center electrode (4) should have
square edges and the side electrode (5) should
not be eroded.
5. Discard the spark plug if there is apparent wear
or if the insulator is cracked or chipped.
6. Check the spark plug gap (6) using a wire-type
feeler gauge. If adjustment is necessary, bend the
side electrode carefully.
The gap should be:
0.8 – 0.9 mm (0.03 – 0.04 in)
7. Make sure the plug washer is in good condition.
8. With the plug washer attached, thread the spark
plug in by hand to prevent cross-threading.
9. 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: 1/2 turn after it seats.
b) Then loosen the plug.
c) Next, tighten the plug again: 1/8 turn after it
seats.
(5)
(4)
NOTICE
An improperly tightened spark plug can damage
the engine. If a plug is too loose, a piston may be
damaged. If a plug is too tight, the threads may be
damaged.
10. Reinstall the spark plug cap. Take care to avoid
pinching any cables or wires.
(4) Center electrode
(5) Side electrode
(6)
(6) Spark plug gap
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