I've got an 04 WR. Boyesen QS2 cover on the accelerator pump, tied up the pump arm, different needle, venturi divider, and it's still possible to shut it off if you abuse the throttle. I did an 07 basically the same, and it had the same issue until we did a 290 big bore kit. Suddenly, it ran utterly linearly from about 2000 rpm to the limiter. I will probably do this on mine this winter, as it's due for a top end anyway.