I am in the process of rebuilding ZRXfool1's CB750K swingarm. He had purchased Honda's bushings and sent them along, just in case they would fit up and I wouldn't need to build custom-fit ones. His pivot shaft was very stuck inside the arm: it took 48 hours of Liquid Wrench to get it out because it was rusted in place. Rusted?
Those bushings are plastic, phenolic or bronze (if aftermarket), how could they rust?
Here's the surprise for ALL of us, since SOHC bikes use mostly the same parts: Honda's replacement bushings are now made from 4130 STEEL. Yes, so is the pivot shaft. This strange turn of events will cause VERY rapid wear and steel-on-steel seizure very soon after installing stock Honda pivot shafts (aka "collar") and bushings, if done today. Those of you who have done this: GREASE OFTEN, like every 2 months or so, to reduce this problem. I don't know why Honda would do this, but it's clear they have.
Steel-on-steel bearings are seldom, if ever, good design practice, and all of my professional career, has been something to shy away from at all costs. They generate tremendous heat, and seizure nearly always results, in tolerances of sub-thousandths systems like these swingarms have.
In addition, the bushings rust. This damages the pivot shaft, making it look like the picture in this post, which came out of ZRXfool1's swingarm. So, keep those steel units greased, and if you frequent the hi-PSI car wash, frequent that grease gun, too!
