Steve I did a lot of things in rapid fashion. IE the BK the E needle and the YZ pipe, so I cannot tell for sure what caused what. What I can say is the combination has eliminated the raising idle as the bike warmed, the "dead" spot just off idle with steady throttle and I can now yank the throttle like a 2 stroke with much better response. The bike hits hard off the bottom now. Everyone says the B/K is a good thing and I won't disagree. What I have not settled out is the high RPM situation. Now it may be that the motor hits so hard down low that the high rpm power now feels weak. Remember I have WR timing. I seem to get different "holes" as I move the MJ around. I got JD's jetting guide and am looking into that right now. I see that moving the clip has a big effect on the mid, even more so than the needle diameter. It runs good but I think there is more there. All in all it runs well all around no fouling (yet!) and no pinging. My advantage to you is that my bike ran good with stock jetting. I am considering putting the WR can back on and trying to get a baseline on the high RPM power to see if I am getting really anywhere. Maybe it is the YZ can that is moving the power down at the expense of some top end. Meantime, let me know if you can source Taffy's air jets in the U.S. It's a proven performer and it don't hurt to try. TC, thanks for the suggestion. Maybe I'll try a EKN on the 4th Later..