Bushes out, and they're plastic:
When I pulled the swing-arm out of the bike, everything was good and snug so I thought some PO might have replaced the notorious nylon bushes. But I guess those are the originals, probably been in there forty-two years? Plastered with grease, which stinks like it's been in there a long time.
The TX750 s-arm has bronze bushes, with spiral grooves in 'em. Left those alone for now.
I'm hoping to use the 750 item, but I need to evaluate the pivot pins and bearing tubes and see which is best & gives the closest fit.
On the 650, the rubber dust caps and the steel shims are kinda bonded together. At least, I think that's what I have unless Yamaha fitted some sort of composite caps in there. The dust caps & shims from the 750 are
knackered. The 750 bearing tube shows signs of grief, half-way along so not in a crucial area, like it has been chiselled at or bashed. Somebody had a struggle or got frustrated?
One complication is that I'm still toying with the idea of wire-spoked wheels. I think SR500 wheels might fit? Point is, if I end up fitting a drum brake, I might need a torque arm fitting
under the s-arm. That's where the TX750 arm has its torque arm fitting already. So, should I modify it or leave as is?
Dilemma. But there's no rush.