I've just got a '01 ttr225 and it hesitates when accelerating hard from a lower rpm. It idles great and the top end is fine also. In fact, you could ride it just a little and not even notice a problem. However, when you are trail riding, it hesitates, misses, etc when accelerating from 2000-2500rpm (I'm guessing). Think of the kind of "snap" you need to pull a wheelie -- you close the throttle and then go wide open. In this circumstance, it hesitates -- I'm pretty sure running lean. It'll do that for one second, and then accelerate hard. Of course this isn't so great for trail riding when you are trying to get the front end light while jumping down or climbing at lower rpm. I've torn apart the carb twice and cleaned everything, although it didn't seem dirty -- maybe a little bit on main jet. New plug too. The diaphragm is in great shape and needle seems to move smoothly. Any suggestions?