Benelli 650 Tornado: the twin that met the Japanese fours

The Benelli 650 Tornado was a 650 cc parallel twin intended to win a share of the American market from the British big twins. By the time it reached production in 1970, however, the Honda CB750 and other Japanese multi-cylinders had already changed that market, and only about 3,000 were built before production ended in 1975.

Benelli 650 Tornado at a glance

Production totals differ between sources: English Wikipedia says about 3,000, the Italian article about 2,000.

History of the Benelli 650 Tornado

An Italian big twin

Benelli had made only 250 cc and smaller machines since the Second World War and wanted to expand, particularly into the American market dominated by British twins. Piero Prampolini, who had designed Benelli’s four-cylinder racers, designed an oversquare 650 cc twin; a prototype was shown at the 1967 Milan motorcycle show. Financial restrictions and disagreements between the Benelli brothers delayed the production line. Renzo Pasolini and the actor Steve McQueen, Benelli’s US ambassador, took part in development; McQueen suggested a Metisse-type chassis and Luigi Benelli designed such a frame. A second prototype appeared at the 1969 Lombard Fair and production began in 1970.

Tornado, 650S and 650S2

The first production bikes went to the United States in 1970, and the model reached Europe in early 1971 with a less restrictive exhaust and larger 29 mm Dell’Orto carburettors. Low-speed handling was criticised, which was blamed on the engine sitting too high in the frame.

After Alejandro de Tomaso took over Benelli in 1972, a revised 650S arrived with an electric starter, a rebalanced crankshaft, higher compression, revised gear ratios and Veglia instruments. To counter vibration, many components were rubber-mounted and weights were added to the handlebar ends. The final 650S2 of 1973 had a higher compression ratio for more low-end torque, further rubber mounting, a humped seat and a clear handlebar fairing.

Engine and reputation

Prampolini’s racing background led to an oil-tight engine with horizontally split crankcases, O-rings on mating surfaces and few external oil lines. The oversquare bore and stroke of 84 × 58 mm allowed large valves, 38 mm inlet and 35 mm exhaust. The cylinders were offset 2.5 mm rearwards to reduce piston slap, and the engine ran in reverse rotation so that the hottest part of the cylinder faced the airflow. The crankshaft ran on four large main bearings, with a flywheel between the centre bearings, and lubrication used a three-litre wet sump. A 360° crankshaft was used, with a five-speed gearbox and chain final drive.

In Italy the Tornado outsold its British rivals, Triumph and BSA. To demonstrate reliability, a 650S2 was ridden continuously around Italy for 25 hours by a team of 18 celebrity riders, covering 2,612 km. Production ended in 1975 after about 3,000 machines, of which half were sold in Italy; the Italian article gives a total of about 2,000.

Design and features

• Racing-derived engine: oil-tight crankcases, four main bearings and reverse rotation.
• American market focus: designed to take on the British big twins.
• McQueen connection: the actor, Benelli’s US ambassador, tested prototypes and suggested the frame layout.
• Development through S and S2: electric starting and rubber mounting to tame vibration.

Benelli 650 Tornado versions

• Tornado (1970–1972): the original model, delivered first to the USA.
• 650S (1972): electric starter, rebalanced crank, higher compression.
• 650S2 (1973): more low-end torque, humped seat, handlebar fairing.
• MotoBi version: the same bike sold under Benelli’s sister brand.

Benelli’s six-cylinder model is described in the 750 Sei article, and the four-cylinder range in the 500 Quattro article. More Benelli models are in the Benelli collection.

Sources

• Benelli 650 Tornado, English Wikipedia: history, engine, versions
• Benelli 650 Tornado, Italian Wikipedia: development, Italian market, production