The crankshaft locked to the dropouts and the crankcase spinning around it, along with the wheel. Talk about a low
I remember some broo hah hah about this engine a few years ago. It's kinda obvious why it won't (when stopped) idle - when it's tooling down the boulevard it's idling! At least what a normal engine considers idling. Or maybe even lower than that.
Maybe when my meds do their thing this morning I'll feel like calculating the RPM at 20 MPH.