The V-Twin is one of the oldest engine configurations and is still widely used today
The V-Twin engine, also called a V2, first came to prominence in motorcycling in the early 1900s, both in Europe and America. A V-Twin engine features a common crankpin for both cylinders’ connecting rods, not only making the crankshaft short and stiff, but also making the whole engine extremely narrow, which is good for aerodynamics, at the expense of cooling for the rear cylinder.
While Harley-Davidson and Indian relied heavily on the V-Twin throughout their entire histories, the configuration dipped in and out of favor in Europe up to the late 1960s, when Ducati and Moto Guzzi adopted the layout, followed by a multitude of Japanese V-Twin designs from the 1980s onwards.
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Indian didn’t invent the V-Twin engine - that honour goes to Gottlieb Daimler in 1889 - but, significantly, Indian was the first American motorcycle manufacturer to adopt the technology for production motorcycles. George Hendee and Oscar Hedstrom, founders of Indian Motorcycle, debuted the first Indian V-Twin design in 1904, largely for the nascent motorcycle racing sport, with a production version being offered to the public in 1906.
Harley-Davidson only released their first V-Twin in 1909. That first Indian V-Twin engine, therefore, set the template for the American motorcycle industry, a template that is still being followed to this day. Harley and Indian were virtually the only two American motorcycle manufacturers - out of hundreds - that survived the Great Depression, but after 1953, Indian ceased trading, leaving the field open for Harley-Davidson to keep the American motorcycle industry alive single-handed until Indian came back properly in 2011 under the ownership of Polaris. Naturally, the engine was a V-Twin.
In the early years of motorcycle manufacturing, many manufacturers used bought-in engines for their motorcycles as the cost of developing engines was beyond the means of many of them. Of all the manufacturers of proprietary engines, possibly the most famous was J.A. Prestwich, otherwise known as J.A.P. Without the J.A.P. engine, many British motorcycle manufacturers would never have got off the ground and, over the years, J.A.P. supplied engines to Brough Superior, Triumph Motorcycles, AJS, Enfield, HRD-Vincent and Zenith, as well as manufacturers in France and Germany. The engine also saw service in cars such as the Morgan three-wheelerThe New Brough Superior Raises The Bar For Exotic Motorcycles, as well as in Formula 2 and Formula 3 racing in the 1950s.
Harley-Davidson engines have always been given names according to their rocker cover shapes. While the 1936 Knucklehead wasn’t Harley’s first V-Twin engine, it was, however, the first Harley V-Twin to feature overhead valves. ‘Knucklehead’ was actually a nickname bestowed on the engine by 1960s-era custom bike builders and came from the shape of the rocker covers, which resembled the knuckles on a clenched fist.
In 1936, the engine was simply known as the ‘OHV’, for Overhead Valve. The Knucklehead engine replaced the old flathead engine in Harley’s top of the range EL models, although the flathead would prove to be extremely long-lived, being offered in the three-wheeled Servicar right up to 1973, as well as being an important engine for Harleys military motorcycles in the second world war. After the Knucklehead, the next two Harley engines would be known by their rocker covers - Panhead and Shovelhead.
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Philip Vincent hired Australian engineer Phil Irving to design a 500cc, single cylinder engine to replace the bought-in J.A.P. engines previously used. Legend has it that Irving saw two engineer’s drawings of the single lying on top of each other, the cylinders forming a V-Twin. Within weeks, the first 1000cc Vincent V-Twin had been built, and the rest is history. The Series A Vincent Rapide’s V-twin engine pushed out 45 horsepower, giving a top speed of 110mph.
The engine was breathed on for the 1948 Series C Black Shadow, which with 55 horsepower, could reach a top speed of 125 mph, making it the fastest production motorcycle in the world. In lightened form and with Rollie Free riding, a Black Lightning set a new world speed record at the Bonneville Salt Flats of 150.13 mph, the resulting picture of Free lying prone on the bike, wearing only his swimming trunks is one of the most famous photographs in motorcycling history.
During the 1960s, Ducati had built a series of excellent single cylinder engines, with shaft-and-bevel drive to the overhead valve gear. In 1970, chief designer Fabio Taglioni started work on a 90° V-Twin, sometimes called an ‘L-Twin.’ Unbelievably for a relatively small manufacturer, not only the engine but a complete prototype motorcycle was completed in six months, and from that day forward, every single Ducati was powered by a V-Twin engine, until the V4 engine arrived in 2018.
Despite this progression to a V4, the Ducati V-Twin remains an important part of Ducati production. The original V-twin engine had bevel drive to a conventional spring-valve cylinder head but then desmodromic valve cylinder heads were developed, where the valve is both opened and closed by cams, with no valve springs. Later, in 1980, the Pantah version of the V-Twin used rubber toothed belts in place of the shaft-and-bevel drive, and it is that particular engine that is the father of the modern Ducati V-Twin engine.
The end of the 1960s and early 1970s saw a burst of engineering activity in the motorcycling world, with new engine designs appearing in profusion. Not only was there the Honda inline four in the CB750, but also the three-cylinder Triumph engine as seen in the Trident and BSA Rocket 3.
A couple of years later, there was the Ducati V-Twin and another new design from Italy: the Moto Guzzi V-Twin. Also, a 90° V-Twin, like the Ducati, where the two engines differed was in the orientation of the engine. The Guzzi V-Twin had a longitudinal crankshaft, the two cylinders mounted transversely, sticking out into their stream on either side of the motorcycle. This design enabled the use of low-maintenance shaft final drive in place of a chain and every Moto Guzzi from that point to the present day has been powered by developments of this engine.
Honda have been eager proponents of multi-cylinder engines since the 1960s, led by their racing engines of incredible complexity and power, often at the expense of chassis development. While Honda’s four-cylinder CB750 didn’t break new ground in terms of engine design, it had a huge impact in terms of sales, and it was the start of Japanese domination of motorcycling that continues today. Honda built a bewildering array of engines, not least of which was the V-Twin in the VTR1000 of 1997.
There was nothing revolutionary about the design, although it was used as a stressed member of the frame, with the swing arm mounted to the rear of the crankcases and the carburetors - 48mm - were the largest ever fitted to a production bike. But, In a performance motorcycle world dominated by inline four engines, the 100 horsepower V-Twin that had mountains of mid-range torque was much more relevant in everyday riding conditions than any screaming four-cylinders.
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At the same time Honda debuted the VTR1000, Suzuki released its own V-Twin engined motorcycle, the semi-naked TL1000S. The engine was a 90° V-Twin, that layout giving perfect primary balance, and featured a combination of chain and gear camshaft drive, which gave the engine a distinctive sound, in addition to the booming exhaust note characteristic of a V-Twin.
Because a V-Twin is a relatively long engine longitudinally, Suzuki developed a new rear suspension system, with a coil spring and separate rotary damper, activated by arms, similar to Formula 1 racing technology. It was innovative, but the oil in the damper could overheat, causing handling problems that plagued the reputation of the bike. Fitting a conventional coil-over shock assembly solved the problem and a TL1000 is still an excellent choice for fast cross-country journeys. The engine would live on in the V-Strom range though, long after the TL1000S went out of production.
Aprilia made its reputation with small displacement two-stroke motorcycles, such as the RS250, with which Max Biaggi won the 250cc MotoGP class three years running in 1994, ’95 and ’96. The engine was actually sourced from Suzuki, who ran it in its RGV250 model and the road versions are now highly sought after. Aprilia then turned to Rotax to build a 60°, 998cc V-Twin engine for its first foray into the big bike world. The resulting RSV in base, ‘R’ and ‘SP’ forms, could attain a top speed of 178 mph from 128 horsepower, allied to excellent handling from the aluminum chassis. In 2004, the name changed to RSV1000R and the bike survived to 2010, when it was replaced by the RSV4. As good as that later bike was, the RSV Mille and RSV1000 represent Italian motorcycle flair at its finest.
KTM built its reputation in the MX and Enduro sports and road bikes were a second priority, but all that changed in the early 2000s, when the 75°, 942cc V-Twin engine, designed in-house by KTM, was launched in the 950 Adventure. KTM had initially tried to use the 60° V-Twin Rotax developed for Aprilia and its RSV Mille bike, but Aprilia refused to share it, so KTM were forced to design their own engine. Continually developed, the LC8’s design parameters of light weight and small external dimensions have been optimized to the point where the engine that now sees service in the 1290 Super Adventure, 1290 Super Duke R and 1290 Super Duke GT, develops a peak of 180 horsepower and over 100 foot pounds of torque. Superb flexibility makes it the perfect engine, no matter the application, and it must go down as one of the best V-Twins of all time.
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.