I also have a orange RD350 that has alot of old school mods, but I'm keeping that.....it runs good. I think I was the only one that ever put aluminum rims on one of those babies.
Orange? Is it a '75? I had a '75. I don't know if I'd call the OEM color orange, it's one of of the ugliest colors I'd ever seen on a bike (about the color of salmon steaks)... so I had it painted pearl black with purple ghost flames. Oh, and I had Akront aluminum hoops laced up to mine, too.
Sorry, I don't have any suggestions for help on your XT...