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2003 manual shift 250 smoking issues


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I am about at my wits end. Took the 250 back to the dealer repair shop AGAIN. Had it in there two months ago for a bad smoking issue. I thought it was to much fuel and washing the oil off the cylinder and burning it. They said it was the head. So I purchased new valves, valve guides, oil seals and had the head professionally done. So $225 later I had a great looking head. Well while I had the ATV apart this far I also got new rings for the piston. Mic'd everything out and everything was in spec. Put it back together and seemed like it smoked a little at the house (5000 feet above sea level). Took it to the mountains (9000 feet above seal level) for Sept. bear hunting and couldn't use it. Smoked worse than before and couldn't run it past half throttle or it would flood itself out. So brought it back home and it is back at the shop again. I say it is something in the carb that isn't set right or wrong jet????????? Anyone have any other ideas that it could be?

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is the smoke black or blue? black is gas and blue is oil, is it gas flooding or oil on the plug? was the cylinder in specs, even below the ring ridge line? did you hone it if it wasn't nickeled? is the crankcase vent line clear? just a few ideas

Smoke is blue, gas flooding is the symptom. Cylinder specd out great all the way. Cylinder walls were as smooth as can be and ran the hone down it one time. Never checked the crankcase vent line. Will do that. Found out that the jets are not correct. Dealer mechanic didn't think to check that until I said something. So we are going for correct jets and see what that does. I'll ask them to check the crankcase vent also. Thanks for your help.

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  • 2 weeks later...
You don't think the flooding of the carb could be washing the oil off the cylinder and burning it?????????////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Ok, got the right jets for the carb and adjusted the valves. Smoke is gone and running great. Final test will be taking it to the mountains this weekend and see how it runs up there.:biggrin:

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