I've had my WR426 for 4 months now and I just found this site. It talks alot about re-jetting the carb, bk mod, backfiring solutions, and yz timing. Lately while riding I too can feel the "lack of punch" my bike should be having. I live in colorado and ride from 7500'-13000'. Could someone help me on getting the right jet and needle settings for my carb for my area. Maybe what others have found to eliminate the bog that I can definately feel now. I really have to jerk the wheel to wheelie over things. It shouldnt be that way with this monster. My bike is stock right now and like many others I know I can get more, crisper power out of this beast. I notice the backfiring alot more now too ever since I read it on this forum. I, like others, want the max out of my bike. Please help!!!