First of all, the discovery was made by Italy’s classic bike mag. Motorciclismo de epoca, so kudos to them
OK, so here’s the story…… Many have wondered why Honda never officially raced the small 500 SOHC and concentrated on the bigger CR750. Well, turns out that there was a one and only official CB500 racer! Built in 1972 to compete in the All-Japan 750 road racing championship, the CB500R was actually a 650 (obtained with 64mm pistons). The bike won quite a few races against much bigger bikes and lighter two strokes in the hands of a certain Kyama.
Other than the big bore kit with sand cast cyl block, bike’s got a dry sump oil system with oil tank, dry clutch, 31mm CR’s, a special chrome-molly frame and bigger valves with a different angle. It weighted only 300 pds and the motor put out 80 hp at 10,700. After these successes, Honda thought about bringing it to Daytona in 73’ but the program was shelved. Maybe because it could have humiliated the macho 750’s….?
Nobody knew about this bike till recently because in 82’ it was sent to a Honda dealership in Italy and Honda never documented it. It was raced only once again in 85’ against much faster F1 750 machines, still finishing in a good place, 13 years after it was made.
500/550/650 pride restored!
TG