I have searched this and other people have experienced this. The posts were old and I never saw a definative answer, anybody figure it out? While riding momentarily the engine will rev as if it disengages for a second or less and only a couple of skips. Doesnt do it all the time. My chains are well spaced on the front chain rings and show no signs of contact, and there is not enough slack any where in the drive for the chains to skip a tooth. The bike shifts perfectly up and down through the gears. Its not jumping gears because the engine speed never changes when the skipping ceases(nor does road speed). Im beginng to suspect the rear freewheel maybe. Any thoughts?