Have found this on german web.
I have seen this thing a few years ago lifely at a motorshow in Dortmund. I talked some small words with the exhibitor/owner. Engine is from a CB500 and has 500ccm. The frame based on a stock twostroker from YAMAHA.
I think it was an aircooled RD. Wheels are magnesium PVM´s. Front calipers some Lockheed´s.
If i remember right he proclaimed a weight less than 140kg /309lbs.
But in my opinion the clutch is the part of interest. The cover is billet made. Clutch basket should be from the CB500. I have heard from another german who raced a CB500 in the days. His name is/was Walter Baumgart(en?).
He built also an dry clutch for the CB500. And by a friend of mine i have sawn a casted cover for a dry clutch.
Unfortunately he sold this item

. I could kill him for that

.
Regards,