Took off airbox and added a foam universal filter. Had to drill out main jet to .033, service department couldnt find right jet to fit the mikuni carb so I just drilled it out to .033. Any more than this it will run rich. Anywhere from .031 to .033 is fine to run. I think this translates to around 85 - 87.5 for main jet size. I also punched out the muffler and removed the spark arrestor. As far as the rev limiter it is governed by the cdi box, so well have to wait for somone to make one that removes the rev limiter. With these mods, we gained a tremendous amount of power. I recommend these for now. It would be nice if anyone else has done anything like this to share their knowledge. Top speed is the same but the time it takes to get there is cut in half and thats with me on it and I weigh 210 lbs. Any questions email me