Back when I was talking to the PO, I asked him to check one thing on the bike for me. The swingarm pivot bolt. On XR250s and 400s, because the pivot blot passes through the motor, it cooks out the grease, the bushings freeze on the bolt, and make it difficult or impossible to remove. It is the achilles heel of these bikes.
I really did not think I would have an issue, since it was fairly new. I was kinda wrong:
I squirted things up, waited a day, and started by tapping on the nut with a plastic hammer, then a ball peen, then a mini sledge. Holy smokes, it would not budge. I then took an old extension and started wailing on it. STILL nothing. So I tipped it 45 degrees, lubed the heck outta it, and went at it the next day. This time I had my wife turn the other side with a ratchet while I pounded. It finally came out:
Pretty surprising how dry and rusty it is, for a bike in that condition. Even left a pile of dust on the floor:
After a lot of wire wheeling. Bolt was fairly pitted:
(sorry, cell phone pic)
Just to be sure, I replaced the bolt and bushing because of the pitting. I probably could have reused them, but bought a new OE bolt ($65....f me.....) from Honda along with new bushings. I saved the old one, just in case. Bearings were fine, only the bushing-to-bolt interface was fouled. Greased everything back up and put the bolt in.
Afterward, the extension became too mushroomed to fit into a socket.