Top 10 Wankel

Jun 15, 2023

They never caught on, but that didn’t stop manufacturers from trying

The internal combustion engine has been with us since the 1880s, but it has remained largely the same in all that time: pistons moving up and down in a cylinder, converting that movement to rotary movement by the use of a crankshaft. One brave and seemingly revolutionary development was the rotary engine, conceived by Felix Wankel in the 1920s and offering advantages in simplicity of construction and power output. However, it also had too many drawbacks to succeed, but this didn’t stop several motorcycle manufacturers not only considering it but putting it into production models, with predictably poor results. Here, we celebrate the motorcycles that dared to be different.

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The very first Wankel-engined production motorcycle, the Hercules W-2000 (also sold under the DKW name in some territories) had a single rotor engine (Wankel engines can have any number of rotors but most commonly single or double rotors) which produced around 30 horsepower, which wasn’t really enough for the 390-pound wet weight. It was also expensive, with Cycle World magazine summing up thus: "Less performance for more money takes this rotary out of the realm of practicality." Further criticized for relatively weak performance, it at least avoided the pitfalls of the Suzuki RE5 (see below) in that it was relatively simple, even if it appealed mainly to those who loved its quirkiness. 1,800 were built, and then the tooling was sold to Norton (again, see below).

It might not have made it into production - only two prototypes are believed to have been built - but it just shows how serious the Japanese manufacturers were considering the Wankel engine and how it was seen as one possible future for the motorcycle. It made its first appearance at the 1972 Tokyo Motor Show and was powered by a 66 horsepower, single rotor engine, fitted into the frame and running gear of the Yamaha TX750, which at least gave it typical 1970s Yamaha good looks. Compared to the two-strokes of the time, however, the Wankel was just too complex and unreliable and the manufacturers had an uphill struggle to persuade customers.

It seems amazing now that a British motorcycle manufacturer, clinging on by its finger nails, should think that using the Wankel rotary engine was a good idea is one of those mysteries of life: quite how this - by now tiny - factory could hope to make a success of the rotary when they knew Hercules had failed is a both a mystery and a shame: without this, perhaps the Norton name would have survived. After messing around with the engine for most of the 1970s, the Interpol ll appeared in 1984 and was only for sale to police forces and breakdown services, such as the RAC. The fairing was borrowed from the BMW R100RT!

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Eleven whole years after Suzuki had abandoned the RE5, Norton finally came up with a rotary-engined model for sale to the public, albeit a very small proportion of the public as only 100 were to be built. It used the same 588cc, air-cooled, 85 horsepower/55 foot pound of torque, twin-rotor engine from the Interpol ll and was a handsome machine, seen by the company as a viable first step back to full production and the re-establishment of Norton as a real player in the motorcycling world. Sadly, the money was never fully there to do things properly and, as in the past, too much money was diverted to racing efforts (even though this amount was also pathetically small) which, even though they were successful, still didn’t persuade the public that this was the right way to go.

Two years farther on from the Classic and Norton is still trying with the rotary engine and would continue for a few years still! The big change for the Commander was the adoption of water-cooling for the engine and, of course, that all-enclosing bodywork, complete with built-in panniers - no-one can accuse Norton of being boring in their thinking. Gradually, the engine was being developed into something that anyone could ride, although it would be fair to say that you would need to be a Norton fanatic to actually choose one over a contemporary BMW or Japanese touring bike.

At the same time as Norton was offering the Commander for sale to the public, the company was actually enjoying racing success with the rotary engines, which makes it all the more surprising that the company didn’t produce a sports bike earlier to capitalize on that success. All that changed in 1990, with the arrival of the F1, clothed in then-fashionable fully-enclosing bodywork, à la Ducati Paso or Honda CBR600, although I would say that Norton did it better than anyone else, perhaps helped by that super-sexy all-black JPS paint job. It was well-made and well-equipped, with an aluminum Spondon frame and high-end WP suspension and many of the bugs had been ironed out of the engine. Only 130 were ever produced, however, so expect to pay a lot for one today.

If the F1 was rare, then the F1 Sport was super rare. More conventional styling that owners could equate to the styling of the race-winning bikes in British Superbikes and at the Isle of Man TT, but it was definitely a case of too little, too late as, by this time, Norton was in its final death throes, which was a shame as the rotary engine had finally come good. The F1 Sport was more an effort to use up the remaining parts at the factory than to attract new customers but looked even better now that some of the bodywork had been cut away to reveal the aluminum frame. An ‘F2’ model was also shown in 1992, which was, if anything, even better looking, but it would never reach production.

Related: 10 Greatest Norton Motorcycles Ever Built

The name of Van Veen was associated with 50cc Grand Prix bikes, as Van Veen was the Dutch importer of Kriedler motorcycles and the GP bikes were known as Van Veen Kriedlers. The first Van Veen motorcycle, however, was as far as it is possible to get from those diminutive Kriedlers, being powered by a 1000cc, twin rotor Comotor Wankel engine, actually developed by NSU and Citroen for use in a car. Power was a claimed 107 horsepower and top speed was said to be 135mph, which was a very good figure in 1978. However, the OCR1000 was not liked by the press and sales weren’t helped by a 700-pound weight and a price tag of $15,000. In the end, only 38 examples were built by the end of production in 1981.

Another prototype that never got beyond that stage, the Kawasaki X99 RCE demonstrated the need of the Japanese manufacturers to stay one step ahead of their home competition or, at least, keep up with them. Featuring a liquid-cooled, twin-rotor engine, both power and torque were at acceptable levels, but the Wankel rotary engine advantages - smooth running - were nullified by the usual problems - mechanical noise at low RPM, weak engine braking, heat issues and much higher fuel consumption compared to a conventional internal combustion engine which, in the era of the oil crisis and high gas prices, was definitely a no-no. Even using chassis technology from the Z1 couldn’t save the X99 and nothing has ever been heard about it since.

So far the only largely successful Wankel-engined motorcycle ever offered for sale. The Suzuki RE5, however, despite having a single-rotor rotary engine, was complex and heavy. There was both oil- and water-cooling, with three separate oil reservoirs - sump, gearbox and a total loss tank whose contents were mixed with the petrol before entering the combustion chamber. The twist grip operated no less than five cables and the exhaust pipes were double-skinned to combat the heat problem inherent in the rotary design. Giugiaro of Italy styled the bike, which included a round, tin can shaped instrument cluster with a sliding cover. The warranty gave some indication of the complexity - full engine replacement for any problem within the first twelve months or 12,000 miles. It was produced for only two years before Suzuki followed the herd and concentrated on its inline four-cylinder four-stroke engines.

Harry has been writing and talking about motorcycles for 15 years, although he's been riding them for 45 years! After a long career in music, he turned his hand to writing and television work, concentrating on his passion for all things petrol-powered. Harry has written for all major publications in South Africa, both print and digital and produced and presented his own TV show called, imaginatively, The Bike Show, for seven years. He held the position of editor of South Africa's largest circulation motorcycling magazine before devoting his time to freelance writing on motoring and motorcycling. Born and raised in England, he has lived in South Africa with his family since 2002. Harry has owned examples of Triumph, Norton, BSA, MV Agusta, Honda, BMW, Ducati, Harley Davidson, Kawasaki and Moto Morini motorcycles. He regrets selling all of them.