Hi Jim !
The requirement for membership is to own a sandcast engine, appropriate vin frame or both.
You have a sandcast vin frame so you are in !
Corbin got married and ran off to Oregon a couple years ago, none the less i will tell him you say hi !
There are other members who can tall specifically what's been done to your engine. I do know there was un-necessary metal in the guide area, in fact i am having my head cleaned up on my unstamped sandcast engine. Am told just that simple clean up in the guide area will give 7-8 additonal hp. Tom Wirth is building that unstamped set of sandcast cases into an engine for me, planning it will be finished and i will pick it up at the end of this month !
I know the CR750 factory kit was major package including not only engine parts but also chassis and body sprung and unsprung parts. This kit gave the engine 90 hp at 10,500 rpm and being the single cam was long and small diameter, shaft whip was a problem.
I have heard private eng.builders would build up heavier cam towers and then use larger diameter bolts going through holes milled through the top of a beefed up cam cover, all in the effort to achieve more rigidity and minimize cam shaft whip.
The exhaust in your pics appear obviously early (rare) Yosh ! The brakes and forks look like modified stock parts or perhaps some pieces are from a factory CR kit.... Is there a brand name on the wheels ?
I am very certain Mark McGrew can tell by looking at the pics exactly what you have and i suspect you don't have a run of the mill period cafe, considering the Yosh connection !
The crank and rods are beautiful !
One could suspect with the "CR" stamped into vin pad, the engine was built to CR specs.........
Love that Yosh decal on the oil tank !
When are you planning on having the project finished ?
You've got a sandcast frame with some very rare racing parts making one very cool race kitted CB750 !
Keep us posted !