Live and learn.
How is the drive quill indexed to the camshaft/cam sprocket? That D-shaped end of the quill has to be oriented precisely for ignition timing.
This explains the reports we've heard/seen over the years about the timing being off so much that the points plate couldn't be turned enough. I've usually assumed a stretched timing chain.
'73 R60/5 Toaster
Luddite. Not just a philosophy, a way of life...