Motorcycle Classics

The Benelli Sei 750

Benelli Sei 750
Years produced:
Total production: 3,200
Claimed power: 71hp @ 8,500rpm (factory rating)
Top speed: 126mph (period test)
Engine type: 747cc overhead cam, air-cooled inline six
Weight (dry): 220.4kg (485lb)
Price then: $3,995
Price now: $3,500-$7,500
MPG: 28-35 (period test)

It was the fall of 1972 when the Benelli Sei 750 was first unveiled before a large audience of Italian dignitaries and journalists from all over the world. As the sheet came off the Sei, the first production six-cylinder motorcycle ever presented to the public, Alejandro De Tomaso made a proclamation: he was declaring war on the Japanese motorcycle manufacturers.

De Tomaso, a well-known sports car builder and stylist, had purchased the venerable Benelli company the year before, and directed its engineers to produce a new motorcycle — and not just any motorcycle, but a beautiful, stylish, well behaved six-cylinder motorcycle with up-to-date components. 

Read Barry Porter’s review of owning and riding a Benelli Sei 750

To understand De Tomaso’s ambitions, some context is helpful. The late 1960s and early 1970s were a time of great flux in the motorcycle world. The end of World War II brought with it poverty for many in Europe and Asia, and a pressing need for inexpensive transportation. In addition, many returning American soldiers had become interested in the motorcycles they had seen — and ridden — overseas.

The American and English factories made a swift changeover from war production to building small bikes for the civilian market, and numerous startups in Italy and Japan began production.

In a few years, the situation had changed dramatically. By the early Fifties, many American motorcyclists had married and traded in their two-wheeler for a washing machine. Indian went out of business, while Harley Davidson eked out a living on police sales. The British factories made money for a while longer, but, claiming they had to keep their shareholders happy, soldiered on with prewar machine tooling. By the early Sixties, prosperity and inexpensive small cars led many of their customers to discard the motorbike for an Austin Mini.

While the British companies were watching their customer base shrink, the Japanese startups had shaken out into a few well-financed survivors, who plowed most of their profits into state of the art machine tooling. In March 1973, Cycle Guide noted, “For the past 20 years, the Japanese have kept buyers in the States to snap up new manufacturing processes and machine tools sometimes several years in advance of the Detroit auto makers.” As a result, the Japanese could build multi-cylinder, oil-tight engines with electric starters, which they sold for a reasonable price.

The Japanese companies also developed an efficient overseas distribution system. Their products began showing up in Europe in 1959, making further inroads into Brit bike sales. Led by Honda, they spent hundreds of thousands of dollars developing the American market.

Most of the Italian motorcycle factories survived the lean times of the early Sixties, aided at least in part by that country’s sunny weather, which makes it more practical to ride motorcycles on a daily basis. Italian manufacturers also benefited from protectionist legislation that made it more expensive to buy imports; and yet the Italian government had to rescue both Ducati and Moto Guzzi before the motorcycle boom of the late 1960s pushed those companies into the black.

By 1972, thanks primarily to baby boomer sales, Harley Davidson was making money again. But the British, unable to keep up, had been decimated, with only Triumph and Norton still standing. The sole survivor of the German motorcycle industry, BMW, was doing nicely selling newly designed opposed-twin tourers. Even so, most of the world market belonged to Yamaha, Suzuki, Honda and Kawasaki.

The Italian motorcycle companies had largely rebounded from the lean years and were ready to go head to head with the Japanese — except the Italian companies didn’t have anywhere near the same resources. Adopting a David versus Goliath mentality, the Italians worked to their strengths: grace, styling and handling.

Benelli is born
Benelli began in 1911 as a repair garage, progressed to the manufacture of parts, built its first complete motorcycle in 1921 and started winning on the track two years later. The factory was destroyed during World War II, but Benelli bounced back and was soon winning races again. When De Tomaso bought the company in 1971, he decided Benelli needed a showpiece — a luxury sporting motorcycle in the spirit of the De Tomaso-designed Pantera sports car.

Within a year, Benelli’s engineers came up with the Sei’s transverse six-cylinder engine, the first to be designed for a production motorcycle. Where the design actually came from is the subject of controversy. Benelli had a history of building racing Fours, but the Sei is not much like them. Many people believe that De Tomaso simply copied a contemporary Honda Four and added two cylinders, and rumors persist that parts are interchangeable between the Sei and the Honda, although the extent of any interchangeability is in question. Other sources opine that De Tomaso was simply following standard automobile practice in the design of the Sei, which makes sense, given his automotive background.

In any event, the bore and stroke of the bike De Tomaso unveiled at his press conference were 56mm x 50.6mm, the same as Honda’s four-cylinder CB500. Other similarities were the single overhead cam run by a chain in the center of the engine, two-piece connecting rods with plain big ends and the Morse Hy-Vo chain primary drive. The engine was only an inch or so wider than a Honda Four with a gap between each cylinder to pass cooling air. It was fed through graceful manifolds by three Dell’Orto VHB 24mm carburetors. The alternator is on the right side behind the cylinders, with the electric starter tucked in nearby. A kickstarter was provided for macho men or a drained battery.

Engines aside, the Sei looked nothing like the Honda. Styled by sports car design house Ghia, the Sei was unmistakably Italian. The cycle parts were Italian designed and built, with a stiff cradle frame that minimized the width of the engine, twin Brembo disc brakes in front, Marzocchi forks and shocks and Borrani aluminum rims.

After the unveiling, De Tomaso showed the Sei prototype at select European shows, but no Sei’s were available for sale for almost two years. A long wait between prototype and production was very typical of Italian manufacturing in the Seventies, but buyers, spoiled by the faster pace of the Japanese factories, became impatient.

A road report finally appeared in the August 1974 Cycle World. The magazine loved the Benelli’s styling and handling, its lack of vibration and the sound, which it said was similar to a V-12 Ferrari. The article put thumbs down to the price (“between $3,000 and $3,500,” a lot of money in 1974) and the handlebar switches, which were noted as difficult to use, and noted that Seis were finally rolling off the assembly line.

Once the Sei’s tooling and production challenges were solved, De Tomaso ran into another problem: distribution. A relatively expensive grand tourer like the Sei demanded a worldwide distribution network — difficult for a small company such as Benelli to achieve.

Ultimately, De Tomaso’s “war” was little more than a skirmish, and the Japanese won. Benelli sold 293 Seis in 1974, 1,479 in 1975, 1,145 in 1976 and 283 in 1977. The Sei was recast as a 900 in 1978, but less than 2,000 were built. MC

Benelli Motobi Club
Official Benelli Web site

Read more about this classic motorcycle: 
Barry Porter’s Benelli Sei 750

  • Published on Jul 11, 2007
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