Honda 2009 GOLDWING GL1800 Owner's Manual page 185

5. Inspect the electrodes and center porcelain for deposits, corrosion, or carbon
fouling. If the corrosion or deposits are heavy, replace the plug. Clean a
carbon or wet-fouled plug with a plug cleaner, if available, or a wire brush.
6. Check the spark plug gap using a wire-type feeler gauge. If adjustment is
necessary, bend the side electrode carefully.
The gap should be:
0.039 0.043 in (1.00 1.10 mm)
7. With the plug washers attached, install the spark plugs in by hand to prevent
cross-threading.
8. Tighten each 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:
DENSO:
b) Then loosen the plug.
c) Next, tighten the plug again:
1/8 turn after it seats.
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.
9. Reinstall the spark plug caps. Take care to avoid pinching any cables or wires.
10. Reinstall the left and right cylinder head side covers.
spark plug gap
3/4 turn after it seats.
1/2 turn after it seats.
Spark Plugs
side electrode
Servicing Your Honda
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