Honda NSS250 2007 Owner's Manual page 127

Spark Plug
8. Tighten the spark plug:
If installing a new plug, tighten it twice
to prevent loosening:
a) First, tighten the plug:
NGK: 3/4
DENSO: 1/2
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 cap. Take care
to avoid pinching any cables or wires.
10. Reinstall the maintenance lid.
118
Servicing Your Honda
turn after it seats.
turn after it seats.