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.The engine was based on the four-cylinder Honda CB500, but with two extra cylinders.The 905cc engine produced 80 horsepower, good enough to push the 484 pound bike up to a top speed of approximately 120 miles per hour.video by: Motorrad Scheunpflug
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 used on the Moto Guzzi Le Mans.
Less than 2,000 were made over four model releases.Described at the time as “outrageous” or a “flashbike”.With rounded bodywork, 6-into-2 exhausts and a bikini fairing, the 900 Sei was a superbikeDespite 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./wikipedia