Benelli Sei

The Benelli Sei is a series of motorcycles that were produced by Italian manufacturer Benelli, and masterminded by automotive designer Alejandro de Tomaso, from 1973 to 1989. Two models were made, with 750 and 900 cc displacement. The 750 was the first production motorcycle with a six-cylinder engine.

Benelli 750 Sei
The Benelli 750 Sei was the first production motorcycle with a 6-cylinder engine and had two model releases. De Tomaso intended it to become Italy's premier sporting motorcycle and wanted it badged as a Moto Guzzi. On its launch, it received tremendous publicity overshadowing all other Italian bikes of that year. It started the trend of angular designed motorcycles moving away from traditional round forms.

The engine was based on the four-cylinder Honda CB500, but with two extra cylinders. The cylinder head fins of the Sei were squared off to provide a cosmetic individuality, but otherwise the engine is in most respects obviously derived from the Honda. The "angular, bold design" was by Carrozzeria Ghia. It produced 76 bhp at 9,000 rpm, had a top speed of around 127 mph and was one of the smoothest European tourers.

Despite the extra cylinders, the Sei's width was kept to a minimum by siting the alternator (which, on the Honda, is at the left-hand end of the crankshaft) behind the cylinders. Cooling was improved by having air passages between the cylinders; the Sei had three Dell'Orto VHB 24 mm carburetors (the Honda CB 500 had four, for four cylinders). The vehicle appeared to reviewers as heavy and cumbersome but handled surprisingly well, and had a unique signature exhaust note from its six mufflers.

Production Frame numbers started at 5000. Production figures were as follows ; Series 1. 1974  293     #5001-5293                                                        1975 1,479    from # 5294 Series 1 ,2 1976    87    from # 6774 Series 2    1977   283    from # 6861 1978 1,058   from # 7145

Sei 900 Series 1     1978     23   # 100001- 100023 Series 1     1979    515   # 100024- and up Series 1/2    1980    322   # 100539- and up Series 2      1981    312   # 100861- and up Series 2/3    1982    176   # 101174- and up Series 3      1983     26   # 101351- and up Series 3      1984    106   # 101377- and up Series 3      1985     25   # 101484- and up Series 4      1986    200   # 101510- and up Series 4      1987     88   # 101710- and up Series 4      1988      0   # 101798- and up Series 4      1989     85   # 101799- and up Total production     1878

The Benelli 750 Six / 900 Six remained the only six-cylinder motorcycle in production until the entrance of the Honda CBX in 1978.

Benelli 900 Sei
In 1979, by which time Benellli had sold 3,200 vehicles, Benelli developed the 750 Sei into a 900 cc motorcycle by increasing bore and stroke, with six-into-two exhausts and a small bikini fairing taken from the Moto Guzzi Le Mans. Less than 2,000 were made over four model releases. Described at the time as "outrageous" or a "flashbike". Flashbikes tended to be "rare, expensive, European, quirky, handsome and high performance". It had an original MSRP of $3,995.



It was later released under the "Sei Sport" name, with a larger bikini fairing.