Yeah Brad, I've done it...or at least I inherited a bike another racers "too hard basket" project and did it a bit better than his attempt. At first glance it looks as if the Honda drops right into the CZ frame but it isn't long before you realise that the drive sprocket is abour three inches higher than the swingarm pivot which causes two immediate problems. 1 chain tension is hard to maintain as the suspension raises and lowers and 2: the centre of gravity is way too high. The ideal is to have the countershaft parallel with the swingarm pivot. I cut the bottom rails out of the CZ frame and chocked the engine in exactly where it should be. I then fabricated a bottom frame section combining an XL250 bottom section with bits of XR500 frame I had laying around. There is a LOT of cutting and shutting involved but if you're handy with the oxy you'll sort it out. Once you've got the XL bottom rails in place you'll notice that the footpegs are in the wrong place. They'll then need to be relocated which isn't as easy as it sounds. You'll also have kickstarter clearance problems from memory. I was pretty happy with the result visually but never rode the bike. I sold it to Ray Atkins who's "gonna finish it one day". There's far more involved than this short description but too many years have past to remember. If I think of any more I'll let you know.
