As I mentioned above, the wheels are CB 500 four. They are identical to those of the CB 550 and CB 750 four, so you can use any of them. You need the fork, the brakes and the brake discs of the four-models also. The fork and the rear wheel fit perfectly into the frame, so its quite easy to do. The parts are easy to find on ebay. Please feel free to contact me (franckwolf@web.de) if you have any further questions.