Keep your Norasaki as is. Does it run?
There was a guy here in Michigan, many years ago now, an experienced road racer, who replaced his Manx motor with a Honda 750. Did a nice job. He was, besides a very good racer, a real craftsman. I never saw it raced because I wasn’t going to all of the races back then. Don’t know what happened to the bike. It was for sale a long time ago for $1,200.
A good friend still has the beautiful Manx with full fairing he extensively raced back in the early 60’s and also has a spare motor. I have a Manx which I haven’t ridden in almost 40 years. Another friend had for a long time an ex Mike Duff Norton factory Manx racer. That friend and Manx are gone now. A long time ago, the three of us took our Manxes to a track weekend at Grattan Raceway in Michigan with the Ducati Owners of Canada, always a fun event. It was open to European and British bikes. No Japanese stuff. We really got a lot of attention. We ran in the 500cc and under group, which was mostly 450 Ducatis. So, we were three Manx 500 ridden by expert road racers, out with Ducati 250 and 450 racers. Easy pickin’. A fun weekend. The DOCC were a great group. In later years I bought and raced Ducatis, and went to their rallys at Grattan and Mosport Raceway in Canada. Mosport is a beautiful track. Many good times there. Love those Canadians and their beer.
Moving forward, a current project of mine is a cafe bike with a 750 Atlas motor in a Honda CB750A frame. Surprisingly, this frame, stripped of all it’s now un-needed brackets is pretty decent looking and the Atlas motor a good fit. Kind of a modern featherbed. Most people will not recognize that it’s a Honda frame. I’m using a Yamaha TX750 front end and rear wheel. The TX750 had beautiful shoulder alloy rims. The seat and tank are cafe stuff from the 60’s, found in the back of my shop. Bike will be a real junk yard dog.