I've got one of those sitting in a shed... mostly all in one piece.
I have a 550 Four, although I need to swap the engine out of it. It's pretty modified, in that it has 6 over tubes, lowered in back, and the rear hub is laced onto a Harley rim. If and when I get around to it, I should put a front brake on it (the rear drum glazes up quick all by itself). I got one off the bike that is the donor for the engine.
Seems the cam chain tensioner in the head sorta got ground to metal filings before part of it fell into the gear on the crank and locked it up. A Bro from Saskatchewan helped me clean that up and put it back together, but the damage was done. It went for one last ride to take a friend's kid to school (the young fellow was being bullied a lot), and the one kid who saw us pull up got eyes as big as saucers when he saw the boy get off. By lunchtime, the bullying was done. I took it home and parked it, and picked up wrecked bike in Scobey MT later for a donor, but by then had bought the Hog and never got a round tuit. Seems I have the time to do stuff, or the money, but seldom both at the same time.