i have a 06 yz 450 i just recently put in some hot cams did the AP mod and jetted for elevation 4200 ft. went riding today and have noticed that it does not want to rev all the way it feels like it hits the rev limiter really quick or somethin. i had a buddy ride it and i was listening while he climbed a hill and i kind of sounded like a vw or a tractor it just sounds kind of wierd comming from the exhaust. other than that it runs fine. just wondering if i need to maybe jet it different i played with the main size i thought it was maybe a little lean so i richend the main two sizes and it still runs the same. do i need to maybe get aftermarket exhaust with the bigger cams now to move more air or should the stock exhaust be sufficient. thanks in advance.