Unexpected Six: 1983 Benelli 900 Sei

The Benelli 900 Sei was part of a quest to secure the seemingly elusive 6-cylinder buyer.

| May/June 2015

1983 Benelli 900 Sei
Claimed power:
80hp @ 8,400rpm
Top speed:
120mph (period test)
905.91cc air-cooled SOHC inline six, 60mm x 53.4mm bore and stroke, 9.53:1 compression ratio
Weight (dry):
484lb (220kg)
Fuel capacity/MPG:
4.4gal (16.5ltr)/35-45mpg
Price then/now:
$5,406 (1983)/$15,000-$20,000

In 1972, Richard Nixon ordered the development of a space shuttle program and David Bowie sang about Ziggy Stardust and the Spiders from Mars. The Summer of Love was long over, and disco, with all of its glitter and excess, was just beginning. In the same year, into this heady stew of women’s liberation and the seemingly never-ending war in Vietnam, Italian manufacturer Benelli unveiled the first production 6-cylinder motorcycle. They called it the 750 Sei — “sei” is Italian for six.

New owners

In 1971, sports car magnate Alejandro De Tomaso purchased Benelli. His immediate plan was to create a motorcycle that would be a Benelli image builder, something people would talk about and aspire to own. He handed the task to his engineers, who were given a short time frame to come up with a line of multi-cylinder motorcycles, a 500cc 4-cylinder and a 750cc 6-cylinder.

He essentially wanted the two-wheeled equivalent of his Pantera sports car, an exotic coupe powered by a Ford V8. Almost immediately, Benelli’s engineers came up with the 750 Sei, and in the fall of 1972, De Tomaso unveiled it at the Canalegrande  Hotel in Modena, Italy. Featuring sharp, angular styling to the fuel tank, side covers and fenders penned by Carrozzeria Ghia, and six chromed exhaust headers with three mufflers stacked on each side of the motorcycle, the 750 Sei demanded attention. When De Tomaso thumbed the starter button and fired the 71 horsepower six, breathing through three 24mm Dell’Orto VHB carburetors, each mounted on an aluminum Y-manifold feeding two cylinders, and revved it up a couple of times, the audience was captivated.

That audience was a horde of motoring journalists, and the subsequent press coverage created an expected stir. But months after the introduction, the new 6-cylinder motorcycles had yet to come pouring out of the Benelli factory.

Production reality

So where was the new bike? According to a late summer 1974 article in Cycle World, this is what De Tomaso did to bring the Sei to the public’s attention, almost a year and a half earlier: “In the allotted time schedule he had but one choice; copy closely a successful existing multi engine design (Honda Four), tack on two more cylinders, hang it in proven chassis geometry and do a big styling number. Spring the package on an anxious press and worry later about producing the thing, because in Italy that could never happen overnight.”

6/25/2015 9:43:17 AM

Sixes are sweeter when you can see the cylinders. I'm sure BMW's K1600 is a far better bike (given its newness) but without being able to see the broad lineup of pipes, it comes up short. The Sei and the CBX were impressive.

bike on highway

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