Called on the xj, didnt sound super promising. The owner has done anything to it besides paint it primer black, and doesnt really know anything about bikes.
I went and looked at the gs450gl. I really liked it EXCEPT it was burning oil out of a coupling in the exhaust, and I couldn't seem to find neutral even with my hand. Other than those two faults I would have made them an offer.
It could just be a goofy neutral indicator switch, i didn't ride it to really get a sense for what it was doing.
Ill post some pics of the engine, and maybe some of you sages could point me to a member or thread where I should direct questions about old UJM's.