Honda UMK425T Owner's Manual page 62

4.Measure the plug gap with a feeler gauge.
Correct as necessary by carefully bending the side electrode.
The gap should be:
SIDE ELECTRODE
5.Check that the spark plug washer is in good condition and thread the
spark plug in by hand to prevent cross-threading.
6.After the spark plug is seated, tighten with a spark plug wrench to
compress the washer.
NOTE:
If installing a new spark plug, tighten 1/2 turn after the spark plug
seats to compress the washer. If reinstalling a used spark plug, tighten
1/8 – 1/4 turn after the spark plug seats to compress the washer.
TORQUE: 11.8 N∙m (1.2 kgf∙m)
CAUTION:
The spark plug must be securely tightened. An improperly tightened
plug can become very hot and possibly damage the engine.
7.Attach the spark plug cap.
8.Install the top cover, and tighten the hex socket bolt with a hexagon
wrench securely.
0.6 – 0.7 mm
WASHER
0.6–0.7 mm
INSULATOR
59