A 60s 650cc Triumph Bonneville is a very good bike. Probably needed the 70s five speed box ?
My problem is, apparently, I was a sucker. I built an original spec ("Production", get it?) bike, and most of the other competitors hot-rodded their engines internally, skirted the rules with alloy wheels, etc. I don't recall if the rules allowed 5-speed upgrades, but my situation was that I had to choose between a BMW R60/5 of dubious prospect, and a Bonneville 650 (which I was very familiar with). I didn't have the play money to source and set up a 750 at the time. Also didn't have a 5-speed cluster available.
Anyway that class has rules that were written to be taken advantage of. As long as the bike APPEARS stock, it can run in the class! There are several alloy cylinders that can go well over 750, be painted black and APPEAR stock. Stroked cranks, high compression pistons, oversize valves, the lumpiest cams you want, anything goes, as long as it loos stock. Oh, yeah, 500cc-750cc is the range for the class, I was the only 650, there were no 500s running, but there was one guy that was quite fast on a DOHC black bomber 450 Honda, and another on a SOHC 400 four. Then again, what would you reckon the disadvantage is on a pushrod twin?
We're far off topic, so that's it for me...
Rest in Peace, William D.