Two Much Trouble: Ducati's Parallel-Twin Engines

A history of the parallel-twin engine saga in Bologna.

  • The first of Ducati’s parallel twin race bikes, the 175cc was nicknamed “Il Testone,” or Big Head.
    Photo by Phil Aynsley
  • Next in line was the 125cc parallel twin GP racer, which used desmodromic valve operation.
    Photo by Phil Aynsley
  • A 250cc parallel twin racer ordered by Stan Hailwood.
    Photo by Phil Aynsley
  • A 1968 500cc parallel twin prototype built with the encouragement of U.S. distributor Berliner.
    Photo by Phil Aynsley
  • The Ducati 500GTL took its styling cues from the unloved 860GT.
    Photo by Phil Aynsley
  • The Ducati 500GTL took its styling cues from the unloved 860GT.
    Photo by Phil Aynsley
  • The 350cc Sport Desmo turned out to be the most successful of the parallel twins.
    Photo by Phil Aynsley
  • The majority of the 350 and 500 Sport models were built at the Italjet plant rather than the Ducati factory.
    Photo by Phil Aynsley
  • The 500GTV debuted in 1977.
    Photo by Phil Aynsley

One of motorcycling’s most enduring designs is the parallel-twin engine, but not all manufacturers have made it a success.

Right now Ducati is proving that if you stick to what you know, you earn trust and buying confidence from your customers. The Italian factory is in the middle of record sales growth. Last year alone its worldwide sales increased 22 percent, with the U.S. firmly entrenched as its biggest market. The trend is expected to continue this year as nearly half its 2016 lineup are new models.

This success is based on one basic engine configuration: the 90-degree V-twin, or L-twin as it’s also called. It is available in a huge range of options, from the detuned, air-cooled Scrambler to the full-on Superbike mode of the 1299 Panigale. The business plan isn’t that much different to those of the major British motorcycle manufacturers of the 1940s and 1950s, which dominated the U.S. market. Their sales platform was based on various versions of the parallel twin.

The parallel twin is an enduring design, first brought into major motorcycle production by Triumph in the 1930s. As the 1960s progressed, Italian manufacturers joined a lemming-like rush to make their own parallel twins. This included Laverda, Benelli and Ducati.

Ducati had earlier experience in this area, developing several parallel twins as pure racers, not street models. Interestingly, Ducati made three stabs over three decades at a production parallel twin, yet none delivered sales success. Ducati’s various attempts at the parallel twin have seldom been documented in any detail. Certainly, Phil Aynsley is the only person to have photographed in detail all the surviving Ducati parallel-twin models. Each is an amazing story.

Twin sports

By the mid-1950s, Ducati’s single overhead cam 125cc single-cylinder was the bike to beat in Italy’s hugely popular long-distance road races. An example of its dominance was when factory rider Giuliano Maoggi won the Moto Giro outright in 1956. Over a gruelling 745 miles, he left the entire 175cc class in his wake. But things were different on the world stage, with both the 125cc and 250cc Grand Prix championships reeling from the dominance of NSU’s twin-cylinder racers of 1953-1954.

11/16/2018 7:14:06 AM

Strange how you say the 250cc twin was a failure 1960. I was at Silverstone the first time Hailwood raced it. I was standing at Stowe; Hailwood was nearly the full length of hanger straight in front of the other guys on the first lap. How is that a failure?? I know he did not keep it long, but then he had the 250.. Mondial that he won so many races on.

1/25/2018 8:10:35 PM

Dear Motorcycle Classics Seeing all this drama of the most famous Italian motorcycles, I observed that the Italians always cared about sportsmanship, to the detriment of usability for a much more numerous and faithful public. If they had designed a 350cc twin cylinder, they could take advantage of 175 engine parts, allowing economy in the production of the models, competing for a brand awareness in several countries. Here in Brazil, models that appear only in Rio de Janeiro and São Paulo are rare in the rest of the 31 states of the Brazilian federation. They have not yet learned the Japanese honey cake recipe. Millions of machines on the streets for people of low purchasing power, sutentando the sophisticated models for a special audience. Unfortunately here in Brazil, is not the time to manufacture or sell anything. After three devastating governments, the Brazilian economy has gone bankrupt, as there are more than 40,000 thieves scattered by the Ministries, regulatory agencies that regulate unprofitable spending and copied swollen payrolls to the power of the judiciary, suffocating middle class and working class workers who both need efficient, rapid, economical and fully reliable transportation for a long time. We expect better days getting rid of these unscrupulous rulers, plus world speculators trying to break the world's barn, Brazil.

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