HI PCMax,
I'm having the same problem with my 84 250. A few guys on this forum suggested I pull the old parts out, measure up the bushes and the swingarm and have new ones made up at a local fitter. I haven't pulled the back end apart yet to see what shape they are but not a bad thought really. For the bearings, I needed wheel bearings the other day and the bearing place around the corner had no problem at all giving me an exact match for the old ones at a cheaper price than I could buy online. I recon the swingarm bearings would be the same.