Thanks, it was a hoot racing. I know the R65 was never designed for racing, but it really does hold its own. Here are the lightweight class specs:
VINTAGE SUPERBIKE CLASS ENGINE TYPE EXAMPLES
LIGHTWEIGHT
Single-cylinder 2v Yamaha SR/TT/XT500 590cc max
Single-cylinder 4v Honda FT500 510cc max
Pushrod twin BMW/Guzzi 650cc max
Multi-cylinder Honda CB350-4, CB400-4, 417cc max
OHC twin Yamaha XS400; Suzuki GS400/450;
Kawasaki KZ400;
Honda CB450T Hawk, 470cc max