Honda XR250 Tornado Owner's Manual page 140

Owner´s Manual
3. Visually inspect the spark plug electrodes for wear.
The center electrode should have square edges and
the side electrode should not be eroded.
Discard the spark plug if there is apparent wear or if
the insulator is cracked or chipped.
4. Check the spark plug gap (2) using a wire-type
feeler gauge. If adjustment is necessary, bend the
side electrode (3) carefully.
The gap should be:
0.80 – 0.90 mm (0.031 – 0.035 in)
5. Make sure the plug washer is in good condition.
(2)
(2) Spark plug gap
(3) Side electrode
(3)
6. With the plug washer attached, thread the spark
plug in by hand to prevent cross-threading.
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: 3/4 turn after it seats.
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats.
NOTICE
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.
8. Reinstall the spark plug cap. Take care to avoid
pinching any cables or wires.
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