Norton made a few rotary-engined bikes through the mid-1980s and early-1990s, none of which were very successful. The 588cc, air-cooled Interpol II police bike, which Norton started making in 1983, had a two-rotor engine which made 79bhp@9000rpm. There was also a civilian version, the Classic. In a later iteration, the Commander, the 588cc rotary engine got liquid cooling, and made 85bhp@9000 rpm.
But the really interesting Nortan rotary is the now legendary F1. The world’s only rotary-engined superbike was hyper-expensive – about US$45,000 back in the early ’90s – but went like blazes. Unlike a conventional piston driven engine, the F1’s 588cc, liquid-cooled rotary engine had no reciprocating mass, and produced 95bhp@9500rpm in a smooth, linear fashion. The Norton F1 RCW588 won the British F1 series in 1989, and the bike was also raced in the Isle of Man TT races. The British Motorcycle Land Speed Record was also set at 307km/h in 1991 using a Norton rotary engine. Steve Spray and Trevor Nation were the two British riders who raced the F1 successfully in various events in the UK.
As you would expect with an all-new engine design, Norton had various problems with the F1's rotary engine, and the British company never really had the money to sort those problems out completely. If only Norton had Honda's financial muscle, the world of very fast motorcycles might have been a different place today…
NRV588 Norton rotary prototype