GN250 engine problems

Clockworkz

New Member
I've been working on getting my 1988 gn250 running. It sat for about 7 years and never ran all that great. I cleaned and rebuilt the carb, replaced the airbox with a cone filter, cleaned the gas tank, replaced the cdi, and now I'm working on getting the engine running smoothly. When I first start it up it sounds fine and idles at a good rate but as it warms up it starts to idle faster. So fast that it doesn't need any throttle to move into first gear. It also starts to smoke at the headers. I'm thinking it is an exhaust leak that can be remedied by changing the copper gaskets. This is my first real project so any help would be appreciated.

I just checked the spark plug and it seems to be fine. Maybe a tad lean but still well within acceptable limits judging from charts.
 
Air leak would be my guess.

Ensure that the seal between the carbs and the head are good.
 
Thanks! I tightened the carb collar, adjusted the needle valve, fiddled with the exhaust, and adjusted the idle screw. Started it up and it worked! Thanks again for the help!
 
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