I have a 400 Xplorer. Its been a great ride and has put up with alot, but one day me and my friend started riding it and it would take off normal, but would rev out at about 20-30mph. The day before, we gave it hell on our dirt road. Had no problems all day then the next day it did this and has since. Its been parked for about a month. Ive done some research but cant find anyone on the web with the same problem. It has a racing cam and been jetted. It will tear out and go. CAN ANYONE HELP ME ?!?! IT WOULD BE GREATLY APPRECIATED.