Bilgemaster, can I get back to your old BSA for a moment?
Are you sure you're talking about the right model? With all the 441 Victor models BSA fitted a proper 6305 bearing in the timing side as well as the NU305 roller bearing on the drive side. Later B50 engines were given a second bearing on the drive side crankshaft. Any bronze bushing in place of the proper main bearing should not have been a factory fitting.
It was the earlier C15 and B40 models which had the plain bush, but this was on the timing side. The drive side still had a proper bearing. Later 250 models (as well as the military version of the 350cc B40) also got the 6305 timing side main.
A.
Sure, I could be wrong or just foggy on the precise details. It's been about 30 years. I only know what I was told at the time about that BSA by the usually ultra-knowledgeable folks at a motorcycle used parts joint in Austin, Texas where I got most of the random bits on the cheap needed to cobble back together the "basket case" Norton N15CS 750 "Desert Sled" I'd picked up near Hearne, Texas (a great place to be
from) for $100, where it had been an unregistered ranch vehicle.
They'd warned me long before it happened of exactly what I could expect with that BSA drive shaft from the company having recklessly cut corners, and sure enough it eventually transpired just as they said it would: the wobbly shaft caused the rotor to grab the stator and Presto!--a goodly portion of the bike's wiring was suddenly inside the primary chain case. The good news was that the Norton was just about roadworthy by then, and I unloaded that crippled Beesa for more than I'd paid for it. I still have that Norton--sorely in need of a rebuild (Hell, it was
already in need of a rebuild for a good chunk of the '90s, when it was my daily driver), but she's in deep hibernation in the shed. Sure, I've been pleasantly distracted by this new-to-me Bullet, but that Norton's next stop on the give-it-some-love train. Promise.