[polgara]

hello everyone,

i started driving a year ago and LOVE it! i’ll hopefully never be without. very happy i found this site, so much great information. i managed to save a few pennies and bought an ’89 ninja 250. she’s my princess well she’s a bit of a “princess” more like a finicky bitch sometimes! just recently she has decided not to stay on she’ll idle with full choke for a bout 2 min and then turn off. she turns off immediately without the choke on. I tried cleaning the spark plugs and found 1 blown (so cool getting my hands dirty like that!) was so excited thought i had fixed the problem however the same thing happened. it’ll drive only if i keep the choke on at stop signs and keep it on prime. um any ideas? i’d appreciate any opinions

[JackTrade]

but given the age of the bike, it sounds like your carbs could be gummed up, and the bike is running too lean, causing it to die w/o being at full-on choke.

Just a thought though…I’m sure others who are better at the mechnical stuff than I will chime in.

[Jeff in Kentucky]

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:

http://www.webbikeworld.com/sea-foam

[TrialsRider]

CV carbs don’t have chokes that block off the air inlet, they have a fuel enriching passage that dumps raw fuel into the intake passageway. Your carbs are not passing fuel through the main jet and venturi where they should be, so by applying the ‘choke’ you are giving it the fuel it needs to run, but not well.
I have no experience with the Sea Foam product Jeff speaks highly of, only tons of practice cleaning carbs the hard way.

[Jeff in Kentucky]

For very long storage, it is best to drain all of the fuel and spray a light oil inside the gas tank, cylinders and carb float bowls. For typical winter storage, you want to keep the gas tank full of stabilized fuel, and the carb gaskets moist with fuel so they do not shrink and crack. Here is some more writing about Sea Foam for some people with old bikes:

http://www.650rider.com/index.php?name=Forums&file=viewtopic&t=3305

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