I have a keihin from a 2000 on the 01, a rad valve, srs piston, and fmf fatty pipe. I also have a fmf gnarly, and stock pipes. I tried somethings this past week with the power valve, added small spring to delay opening, adjusted to open about 3/4, went back to stock setting and tried the gnarly which seemed to help. The gnarly feels like it pulls a little better down low and not as much on top. I also tried a small flywheel weight but didn't notice much difference with it.
I think I can get rid of some of the hit by going back to a oem or wiseco piston but I don't see getting this engine where I will be 100% happy with it (my 96 cr 250 had close to perfect power for me). I may just put the 03 engine in and see how I like it.
Thanks again for the reply and suggestion on the carb.