I have a sportsman 700efi that is cutting out at 40 mph at full throttle. I took it to a shop and they put a uni air filter on it and a new belt. Seemed like it helped for about 2 days but now its doing it again. It's showing no codes. Just wondering if anybody has any ideas. Thanks

 

Is the engine cutting out, or does it just feel like it is slipping. Sounds like it isn't getting enough spark maybe. Did they check the spark plug to make sure it wasn't fouled. If not, that would be the first place I would look.