Honda HRA-21 Owner's Manual page 27

Standard Plugs: BMR-6A (NGK) or W20MR-U (ND)
I
1. Disconnect the cap and remove the spark plug.
2. Visually inspect the plug. Discard the plug if it is
heavily deposited or if the insulator is cracked or
chipped.
3. Measure the plug gap with a wire-type feeler gauge;
it should be 0.6-0.7 mm (0.024-0.028 in). If ad-
justment is necessary, bend the side electrode care-
fully.
4. Make sure the sealing washer is in good condition,
then thread the spark plug in by hand until it seats.
5. Use the wrench to tighten a new plug l/2 turn fur-
ther to compress the washer. If you are reusing the
1
plug it should only take l/8 - l/4 turn after the
plug seats.
6. Replace the spark plug cap.
0.6-0.7
mm
(0.024-0.028
in)
SPARKPLUG
25