I bought one last year that a would-be Cafe Racer kid bought, pulled apart, chopped up the wring loom and then decided he was in over his head and advertised on FB. I offered him the asking price if he delivered it and he was only too happy to, for a fist full of dollars.
It was very rough, hadn't run in 10 years, but he'd bought a few new parts and importantly, it came with a set of Brembo calipers which I've put on my Kawasaki KZ1000 hotrod. Luckily enough he hadn't thrown too many of the original items out, so I reassembled what was there, and was able to buy some parts locally from a nice Vietnamese guy who has a love for Yammy 650's.
I've bought an original seat, a better tank (the one that came with the bike is held together with bondo, paint and not much else) and will eventually install the new wiring harness, sidecovers better brake calipers etc that I've bought for it. What I did like was that once I cleaned the carbs and hotwired it, changed the oil and cleaned the mesh filter it started right up after only a couple of kicks.
XS650's don't do anything really well, but they're a tough old bike and enjoyable cruisers.