1978 Benelli 750 Sei Review
At the time of the Sei's unveiling, Benelli had been rescued by wealthy Argentine industrialist and fan of all things fast, Alejandro de Tomaso. Fresh from selling off a bundle of Ford Motor Company shares (and after creating sportscars like the Pantera, Mangusta, etc.), the turnaround of Benelli represented his next challenge. Benelli was in serious financial trouble at the time, so de Tomaso came along at the right time and picked up the 50-year-old Italian marque for a steal. Soon after, in December, 1972, de Tomaso also purchased Moto Guzzi, which later led to some shared components between the two brands.
Naturally, being the first of its kind, the Sei made a major impression. Rightfully seen as a milestone in the history of the motorcycle, the initial interest cooled in the long lead time between the Sei's unveiling and its eventual release into showrooms around the world. Unveiled in 1972, the 750 Sei wasn't released until almost two years later! The specification that was eventually released consisted of a 747cc SOHC six cylinder laid across the double cradle frame. The engine was fed by a trio of carbs, each of the 29mm Dell'Ortos feeding two cylinders. This unusual '1-into-2' carb layout allowed more space for the rider behind the engine's outer two cylinders. The rest of the essential componentry was fairly conventional: five-speed manual transmission; chain drive, telescopic front forks; swingarm/twin shock rear; twin front disc brakes and drum rear.
Engine aside, the standout feature on the 750 Sei was the exhaust system. The 6-into-6 pipes splayed out with three on each side, with upswept silencers that evoked the look of Triumph's X75 Hurricane. The long fuel tank featured a blacked-out front section that masked its length. Styling was modern for the time, with angled lines. The appearance was compared to a number of other bikes, but perhaps most closely resembled the Moto Morini '3 ½'. The gauges were also unusual for the time in being encased in chunky square housings. Chrome mudguards front and rear, a slim but comfortable seat, free-standing headlight and black-painted frame completed the Sei's styling features.
Specification barely changed over the years, so the last 750 Sei to leave the production lines before the introduction of the 900 Sei differed little from the first example from 1974. However, there are two distinct eras for the 750 Sei, and the 1978 models fell in to the 'Series II' category, which covered 1975-78. Poor manufacturing tolerances led to gearbox and crankshaft failures on the earliest 750 Seis, but by early 1975, these problems had been identified and remedied by Benelli, leading to the Series II designation. Beyond the engine and gearbox fixes, Series II models also featured Moto Guzzi-derived front forks (replacing Marzocchis on Series Is), and the addition of four more colours - black, grey, metallic blue and gold - to the originally-offered red, silver and metallic green.
Despite its engineering innovation, or maybe because of it, the Sei failed to win the heart of buyers. So much had been made of the uniqueness of the six-cylinder engine in a roadgoing motorcycle, that the reality was always going to struggle to equal the dream. The 750 Sei had a lot of good points, like the twin front disc brakes, which were arguably the best available in the late 70s, but where the Sei really excelled was in its smoothness. Power delivery from the seven-bearing six cylinder engine was exceptionally smooth, which combined with the exceptional handling, made the Sei a real treat to ride.
So if it was that good, why wasn't it more popular? For all its good points, the Sei was something of a "not quite" bike - not quite a sportsbike, as it lacked the outright speed, and not quite a tourer, as it lacked the fairing protection and softer suspension that characterised these models. Even amongst its Italian brethren, the Benelli was the odd one out. Ducati had the sports side of the market, Moto Guzzi the touring & cruising, and MV Agusta the high-end racers, so the Benelli sat in a curious middle ground - jack of all trades, but master of none.
The Sei also suffered against Honda's CB 750/4, the king of the road bikes at the time. The CB 750 was just as quick as the Benelli, arguably better put together, but more importantly, it was significantly cheaper - close to half the price of a Sei when new. While the Sei did a lot of things as good as the CB750, it wasn't noticeably better in any area, except handling.
Today, the main appeal of the Sei, indeed with any Benelli from this period, is its rarity. Only around 3,200 were made across the four years of production, so it's by no mans a common sight. It's not often you see a Benelli for sale, even more so a 750 Sei, despite it being one of Benelli's most significant models. That same rarity means parts are harder to track down, but brings with it its own appeal as something different from the rest of the herd. Go to an Italian bike show and you'll be drowning in Ducatis and Moto Guzzis. Benellis, on the other hand, can usually be counted on one hand. With its broad engine and those six pipes, the Sei has an unmistakable presence, whether stationary or in motion.
While most of the Seis still in circulation today have been left largely untouched, some have had aftermarket oil coolers fitted to prevent overheating, with modern electronic ignition another common upgrade. These make the Sei less prone to potentially disastrous - and costly - mechanical failures, so unless you're an "original" purist, these upgrades are worth doing.
If you love Italian bikes, and are looking for something out of the ordinary that's as comfortable commuting as it is on short-hop touring, it's hard to go past a 750 Sei.
SPECIFICATIONS - 1978 Benelli 750 Sei Series II (aka 750/6)
Frame: Double cradle-style steel tube
Engine: 747cc SOHC 16-valve four stroke six cylinder
Bore/Stroke: 56 x 50.6mm
Compression: 9.8:1
Power/Torque: 71bhp @ 8900rpm / 15ft/lb @ 6850rpm (claimed)
Induction: 3 x 29mm Dell'Orto carburettors
Starting: Electric/kick
Cooling System: Air
Electrical System: 12 volt
Transmission/Drive: 5 speed manual/chain drive
Front Suspension: Telescopic forks with 5.5 inch travel
Rear Suspension: Swingarm and twin shock absorbers with 2.5 inch travel
Front Brake: 2 x 11-inch (280mm) discs
Rear Brake: 7.9-inch (200mm) sls drum
Front Tyre: 3.50 x 18
Rear Tyre: 4.25 x 18
Weight: 220kg dry
Wheelbase: 56 inch (1422mm)
Seat Height: 33 inch (838mm)
Ground Clearance: 6.5 inch (165mm)
Fuel Capacity: 5 gal (22.5 lt)
Top Speed: 180 kph (approx)
