I have a little update. I was having a top-end problem in that I couldn't reach anywhere close to the RPM limiter. I found that my prefilter on the mushroom filter was being sucked-down to the filter so I removed it and changed the dual stage filter material to a single stage. Today I took it for a run. It helped..but didn't cure the problem. As it reaches speeds over 50 it seems the higher it gets, the longer it takes to get there. Its like its fighting something. I did reach 65 but still had a ways to go to the limiter. I opened my flip windshield and although I don't want to go past 40, it did reach 40 much faster open then closed. So..maybe these windshields and rear shields are having more effect on these then we think.