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Spark plug – HONDA CRF50F User Manual

Page 88

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0.024

0.028 in (0.60

0.70 mm)

80

Spark Plug

Servicing Your Honda

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.

Tighten the spark plug:

Disconnect the spark plug cap.

Clean any dirt from around the spark plug
base.

Remove the spark plug with a plug wrench.
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.
Check the spark plug gap ( ), using a wire-
type feeler gauge. If adjustment is necessary,
bend the side electrode carefully. The gap
should be:

Make sure the plug washer is in good
condition.
If you have to install a new plug, first check
the gap.
With the plug washer attached, thread the
spark plug in by hand (to prevent cross-
threading).

If the old plug is good:
1/8 turn after it seats.
If installing a new plug, tighten it twice to
prevent loosening:

First, tighten the plug:
NGK:

turn after it seats.

DENSO:

turn after it seats.

Then loosen the plug.
Next, tighten the plug again:
1/8 turn after it seats.

Reinstall the spark plug cap. Take care to
avoid pinching any cables or wires.

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