May 24, 2010 at 6:12 pm
#26696
Jeff in Kentucky
Participant
Most likely, the idle circuit inside at least one of the carbs is clogged (most likely the carb for the cylinder with the dirty spark plug, since I think this 250cc Ninja has 2 carbs), from improper storage while the bike is parked for weeks at a time. To prevent this in the future, add a fuel stabilizer to the gas tank, run the engine enough to get it into the carbs, and leave the fuel valve on all the time, so as fuel evaporates from the carb float bowls, more fuel comes from the gas tank to keep them filled.
My favorite Sea Foam article, about a first attempt before taking the carbs apart for cleaning: