That's a strange one bro - my motor's revs sometimes hang a little high (3000rpm) for a second or two before the powervalves move, then the revs drop to tickover normally. So maybe check the powervalves are moving through their range ok and responding to throttle movement as they should.

Errr, whenever anyone says anything about the revs creeping up or staying high i instantly think air leak so i guess that's a possibility - maybe when you put fresh pistons in it you should do a leak down test if you haven't already?

Are the carbs definately snapping fully shut on their own?

Is it running 100% normal when you first start it up?
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