25th January 2023

Motorcycling Landmarks: The Norton Rotaries

From ‘burnt offerings’ to TT victory, the Norton rotary engine epitomises the ‘never say die' spirit that endured through the darkest days of the collapse of the original British bike industry. Burnt offerings? That was how Bert Hopwood, engineering director of the BSA-Triumph group, described the engine parts he frequently inspected during the early years of development.

After the collapse of NVT (Norton Villiers Triumph) in 1975, a small team of engineers was retained by what remained of the Norton company at Shenstone, near Lichfield, to continue the development of the rotary engine. They had to overcome some serious problems including severe overheating, poor idling and a number of difficult materials issues caused by the unique construction of the rotary.

Gradually they beat their way through all the obstacles and in 1984 Norton began selling the air-cooled Interpol rotary to police forces and fleets including the MoD and RAC. The Interpol was a fully faired machine with 85bhp and a nominal 588cc capacity. In 1987 the general public got their chance when the Classic was launched; a limited run of 100 bikes with traditional unfaired styling, destined to become collectors’ items.

To improve reliability, the rotaries switched to water-cooling in 1988 and the styling of the police models was updated with a sleeker fairing and integrated panniers. This model, called the Commander, was also available to the general public with a dual seat and was well regarded as an ‘all day’ touring bike.

In parallel with the road bike development, from 1987 onwards Norton began a low-key operation to tune the rotaries for racing, eventually achieving a very competitive 130bhp. Throughout 1988 and 89 the rotary Nortons set lap records at circuits all around the UK. In 1990 Norton capitalised on their racing publicity by launching the Norton F1, a stylish Supersports model finished in black and gold livery to mimic the racers and priced at £12000.

But the biggest story was yet to come. In the 1992 TT races, Norton entered Steve Hislop on a shoe-string budget. After a furious battle over six laps in the Senior TT, Hislop won by just four seconds from Carl Fogarty on a top-spec Yamaha; the first Senior TT win for Norton since 1961! The pace was so hot that the third-place finisher was two minutes behind and fans still consider it to be one of the finest duels ever fought out on the Mountain course.

Despite the race victories, Norton was in financial trouble again and crashed owing millions, having manufactured and sold fewer than 1000 rotary machines in total. Though Ian Simpson won the British Superbike Championship in 1994 on a rotary, by then the Norton company was effectively finished.

Even today, Norton rotaries are highly prized by their owners; whether for the exquisite looks of the F1 or the long-distance stamina and comfort of the Commander. Though other companies, such as Suzuki, DKW and Van Veen, produced rotary-powered machines, arguably none made as much impact on motorcycling history as Norton.

Did you know the story behind how they came to be? Let us know in the comments below!