The 18" rear wheel is off a '77 Standard. Somebody brought the remnants of one to toss in my dealer's boneyard. It was just a chassis, no motor or bodywork. They brought it in the trunk of their car and to get it to fit, they cut the steering neck w/ forks off the front of the frame, lol. I just happened to be about to bring my dealer a junk XS500 (or was it a KZ440, lol) and I offered to trade him. He said fine. This was a good score on my part - flanged allow wheels, good fork set w/ gauges (and a key), side and centerstand, lots of good stuff for free.