Honda CB250 Nighthawk Owner's Manual page 156

SYMPTOM: Engine starts, but runs poorly. (cont'd)
POSSIBLE CAUSE
sooty exhaust (rich fuel
mixture)
detonates or pings under
load
afterfires (backfires)
pre-ignition (runs on after
ignition switched OFF)
If Your Engine Quits or Won't Start
See your Honda dealer.
If applicable, switch to the recommended octane
gasoline (page 73
gasoline. If the problem persists, see your Honda
dealer.
See your Honda dealer.
See your Honda dealer.
Taking Care of the Unexpected
WHAT TO DO
) or change your brand of
147