I have a 96 sportsman 500 4x4. It starts ok revs up good till thto unt thumb throttle gets about 1/2 way then it seams to break up. At an idle it seams to speed up and slow back down at random, not much but noticeable. I got this as a project as I'm getting to old to hunt without some help if I get something. I had done allot of reading and even had a friend who worked on these things help. From the start after I got it all together the same problem with the breaking up has been happening. Change the cam, valves and rockers. Change the carburetor. Changed the CDI. Cylinder and rings good. new top end gaskets. Checked the timing, good. Compression good. Unhooked the reverse limiter. All new parts still the same. Is there some sort of over rev setup on this motor if the limiter is unhooked???? At a loss, I have a $1000.00 in new parts a little better but still the same. At a loss need help.