From Honda Wiki
The Honda CB500 four, introduced early in the 1970's, was similarly styled to the CB750, but smaller and lighter, with an output of 48bhp and a manufacturer's specified top speed of 102 mph.
Like the earlier CB750 it sported a single front hydraulic Disc brake, rear drum brake, electric starter, and Single overhead camshaft (SOHC) 8 valve engine. The 4 into 4 exhaust pipes made it easy to identify. It was thought to be a better handling bike than the larger model, although it weighed in at 420lb (dry).
A number were raced in the Production TT races on the Isle of Man in the early 1970's. Bill Smith won the 1973 500cc TT Production race (4 laps) riding one, by only 8.2 seconds from second place Stan Woods mounted on a Suzuki T500 two stroke twin.