Rare Perfect Example of the World’s First Six-Cylinder Motorcycle

Most two-wheeled devotees are familiar with the legendary six-cylinder Honda CBX, which made a significant impact upon release in 1978. However, the Italians beat Honda in producing the world’s first six-cylinder motorcycle with the Benelli Sei, like the one for sale now on eBay.

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Humble Beginnings

Founded in 1911, Benelli spent most of its first decade repairing bicycles and motorcycles for the World War I effort in Italy. By 1919, it had produced an original motorcycle using an adapted bicycle frame and a modest 75cc, single-cylinder motor. Two years later, the company came out with its first machine built entirely in-house.

Inspired by British engineer Edward Turner, Benelli produced a sophisticated and highly-successful overhead-cam 175cc single-cylinder engine in 1927. That achievement firmly established the firm’s engineering credentials.

A couple of years later, Benelli produced a competition version of the 175cc. With the youngest Benelli (Tonino “The Terrible”) at the controls, the new bike crushed the competition, winning four Italian championships in five years.

After developing a successful twin-cam version of the 175cc motor, Benelli demonstrated lofty racing ambitions by producing a supercharged four-cylinder, 250cc engine. With this screaming motor (55 horsepower at 10,000 rpm) and success at the 1939 Isle of Man TT races, Benelli dominated the track between 1927 and 1932.

However, World War II brought hardships for Benelli and most European car and motorcycle producers. In survival mode, the firm shifted from racing to producing modest models to help get Italians mobile again.

Origin of the Benelli Sei

The massive influx of Japanese motorcycles in the 1960s set new levels of performance and economy for the motorcycle industry. Benelli struggled during this era until famed Italian-Argentinian industrialist Alejandro de Tomaso purchased the Pesaro outfit in 1971.

Wasting no time, de Tomaso challenged his engineers to copy the superb four-cylinder engine used by Honda in its CB500 Four—saving time and money on development. It worked, but DeTomaso wanted more. He aimed to produce Italy’s finest sporting motorcycle, tasking engineers to add another two cylinders to the 500 Quatro motor.

In 1973, the Benelli Sei was born as the world’s first six-cylinder motorcycle engine. Sei is Italian for “six.”

A Low-mileage Survivor

Reviewers of the time warmly welcomed the Sei, which was styled by the famous Ghia design house. The bike featured a huge twin-disc Brembo brake setup at the front, six chromed exhaust pipes at the rear, and tanks and panels with crisp styling.

But the star of the show was the engine, with its six cylinders laying transversely across the frame. The factory-rated peak power for the 747cc motor was 71 horsepower at 8,500 rpm. Contemporary testers recorded a maximum speed of 126 mph.

Cycle World magazine described the sound of the Benelli Sei as “similar to a V-12 Ferrari.” At around $3,500, it was a costly machine. The high price and a patchy distribution network helped make Sei a rare, sought-after exotic motorcycle. This example on eBay is a later Series II model with 90 miles of use after a sympathetic top-class restoration.

The Benelli Sei’s $24,000 asking price seems steep. But with its Italian heritage, beautiful design flair, and intoxicating exhaust note, it’s one of the most collectible sporting machines from the 1970s.