Hard to say about the flywheel nut at first glance it looks like something may have bounced around in there but then it makes me think of timing marks that were used with a pointer because of how they're spaced. The man who mentored me some for engine building raced English bikes and used to rebuild some for those who came looking. He would replace those bronze bearings by heating/expanding the case and then fitting them in on the Brits. I learned some static timing on BSa motors that were void of timing marks so you had to be right on twin or you bust a piston easy or melt one out with early or late spark and too lean. I don't know if that could happen on a single its been such a long time I should just be quiet. English bikes were a work of art in my mind compared to the hd which was center stand roll rear tire to gap opening tdc valves closed then bang but cool too in they're own right. I'm going to get another (English) one day after looking at all this.
