It might be. I only paid 20$ for it so i think I got a steal. It turns over smoothly and there are now scratches on the cylender walls. It might be an 80s model. Im completly guessing off pictures from ebay. The only thing I saw was the camshafts are missing. Anyone know anything about the mechanics of these motors / trannys?

 

I'm guessing it's at least an '80, or '81. It has the emissions valve cover on it which I believe would be early 80's.

You may try a motorcycle salvage yard to identify that block.

 

THE ENGINE IS A 78-79 KZ650B. ALSO THE VALVE COVER IS ON BACKWARDS.

 

I ALSO HAVE 2 SPARE ENGINES.ALL THE PARTS YOU COULD WANT FOR THAT ENGINE.

 

Thanks for piping in! Dang, my guess would have be wrong then.