Guys, I have a bayou 250 that has never idled properly since I bought it new. Well after the first ride. It wants to idle but sputters out. The bike cranks riten up though. I have never adjusted the valve clearance initialy, is that the problem?. The atv will idle at a high rev when the choke is partailaly on. But I would like to fix that. Any Ideas? If the valve clearance is it, how do i do that?[/align][/align]Any one got a shop manual for this quad? klf 250-a1 2003[/align]

 

I have the same problem i bought mine when it was just afour months old and i replaced the spark plug it helped but not fully. Its the only reason i wanna sell it. Mines a 2004 and hasnt had 10 tanks through it since in it entered service in March 05 i bought in July 05

 

Check your plug reading.
If that looks fouled, you may need to lean out a bit by changing the main jet size. Also, check to make sure that choke cable plunger is not sticking inside the bore.

 

I have fixed dozens of these problems> The model was retuned from the old bayou 220 to the new 250 for emission reasons.
Let me tell you how to fix it. You can stop by any motorcycle repair shop and ask a mechanic for one of the washers for the jet needles out of an old jet kit. May sound weird, but this washer used for shimming needles in carburetorsfor jet kits, andis perfect for this repair. There is several more than ever needed in a jet kit so if the guy looks at you strange, go elsewhere to a shop that retunes bikes and they will probably give this to you at no charge.
Now turn off your fuel, and loosen the carb with a phillps screwdriver, turn the carburetor to the right side as if you were sitting on the unit. The top of the carb has a cable guide preventing it from going left. Slide the rubber boot up and unscrew the top of the carb. Remove the slide from the carburetor and compress the spring allowing the cable to be removed from the slide. Once removed there is a spring clip in the slide. Pay close attention to it's location and slide it out by pushing gently on the needle sticking out the lower side of the slide. Once removed take out the needle and apply the washer to the underside of the head of the needle and assemble in reverse. This allows the needle to raise up approx .020 allowing a smooter fuel transfer at idle. IMPORTANT NOTE!!!!!!!!!!!!!!!!!!!!!! When instaling the slide into the carburetor, take special care to not bend the needle, and notice that there is a slot running the length of the slide. This has to line up with a tit inside the body of the carburetor. IF not properly installed the unit will crank nearly wide open when you start it possibly causing damage to the engine components. Operate the throttle and check for full movement of the lever with spring tenson the entire travel of the slide. When in doubt check it twice. Once reinstalled tighten all loose fasteners and turn fuel back on. The problem should be noticably better.