I put a video on facebook about a 90degree 750 which resulted in this comment from John Hewitt:

"Does anyone remember Neil Miles BSA outfit in the 1970s. I raced an A65 for a few years and it was more than a match for most Kettles, Honda 4s etc but when the Z1 came along I changed to one. At a British Clubmans race late 70s and most of the grid was TZ Yamahas. I beat most of the Yamahas so you can tell my Kawasaki was pretty quick. At the finish only 2 other 4 strokes beat me. Another Kawasaki and Neil Miles BSA. He didn't get a better start than me he actually passed me on the straight. I could hear it thumping up behind me and was amazed when it came by. If I was amazed imagine all the TZ Yamahas behind us. That had an uneven beat and it was suspected that it had an unevenly firing engine but of course in those days little was known about the advantages. Maybe he was 30 or 40 years ahead of the rest of us."

I just like the sound of this 750 and how sweet it is.