[mickmate]

If you rev it standing still it is barely noticeable. It's almost the same as going up through the revs where you just feel it. If I stomp the clutch as it's going down and thru the 2100 shake it stops immediately but it also is out of the rev range immediately. The driveshaft was so close on balance (partly cos they're so short) he ground balanced it rather than add weight. The motor has not been touched since dyno other than putting carb and TP on and adding the log and retorquing the two manifold bolts. It does it in every gear so it's not driveline I'm thinkin. It does feel like the flywheel area and shakes back from there. The engine builder and the flywheel/clutch supplier all agreed it was zero balance on both their assemblies and they didn't need to be balanced assembled. I just checked the timing it's at 16 deg at idle. Balancer nut is tight. They are good suggestions thanks. If this thread gets hijacked I'm unsubscribing to my own thread.