1998 Bayou 300 4x4, runs rough, but guy said it has a new carb.

[WillrogersII]

Just picked up a 1998 bayou 300 4x4, runs but spits and sputters. runs worse when i put on the air filter. guy said it has a brand new carb. Does adjusting the valves help with the cold start and not run right until it warms up?

[kp3004x4]

Just have a problem of sorts on a 300 with new aftermarket carb. I have narrowed it down to the temp sensor on carburetor making it read the wrong temp , wouldn't idle until warmed up and takes awhile to crank will let you know what I find out in a few days ,have others I have to get to first.

[Jim Denton]

Yes a valve adjustment can help with cold starts. Chinese carbs are hit and miss on quality and can be a bear to dial in. Personally I'd look at ebay for a used oem. There's no temp sensor on that carb.

Edited April 8, 2023 by Jim Denton

[Gwbarm]

Aftermarket carbs tend to run too lean , definitely better to try and pick up OEM as Jim suggested, but you may try the air fuel mixture screw, generally located on the bottom of the carb pointed straight up, easy to miss, and see if it helps.

[kp3004x4]

Yes better to go with oem if you have the money 

[Mech]

People fit aftermarket carbs when all that's needed is a careful clean and adjust a lot of the time, or to see if it makes a difference to their badly running bike.. It's better to clean and adjust the original carb in most cases.

The only bit that wears is the slide and the body where it runs. If that bit's badly worn and causing a problem(hardly ever), then buy an aftermarket of the same make and model, then change all the old brass jets except the float needle and seat into the new carb body.

[kp3004x4]

Yes have changed out new brass to old carbs several times and ran better than new.