http://www.gadgetjq.com/keihin_tuningparts.jpgCredit to my fellow Brett on the chart here. Should we have a bibliography on our post
So vacuum is ok. Obviously not main since cool past 3/4 throttle. Could be a shim would help or the pilot screw. My opinion put in the 45's and adjust the air screws accordingly. Then try the shims. Like a trial study. You should only change one variable at a time or you don't know what is helping or hindering. Really pilots are idle jets per chart.
Does she back fire with the stutter or bog down. Backfire is lean and bogging is rich. Then there is "falling on her face" which is vacuum. I know really scientific there.
