Just picked up a 2003 WR450 with the free mods done. The bike seems to hit a rev limiter or the same feel every once in a while when coming through 2nd and 3rd gear. What set up are you guys running in the carb? I am at 1500' with a silent insert put back into the gutted exhaust and still using the stock spark arrestor screen. The bike will start with no choke and doesn't feel like it needs much warm up time. If I try to hold a steady RPM in nuetral the bike does sputter a bit. Wack the throttle and it hits hard and fast. Any clue's?