chain shutter

hey there guys, i have been lookin everywhere for a solution to this problem and have found nothing! :(:banghead: Basically i finally got my 80 xs650 hardtail on the road and got all the bugs worked out but one! when i get to mid - higher range RPMs my drive chain starts flailing and slappin...

I have a 72 xs with 11,000 miles. When the clutch fully engages I hear a noise like the chain or clutch is shuttering. It's very brief and just at the last moment the clutch engages. It almost sounds like the chain jumping is jumping a tooth. I recently installed a new chain and front sprocket...