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Technology: MV Agusta F4-750

Genius and madness

…are often close together, as is the case with the design of the new MV Agusta: it offers ingenious design and sensational technology at an amazing price.

A cluster that hangs high – so judged Ernst Leverkus in his first driving report on the MV Agusta 750 S in 1972 – a motorcycle that technically and visually reflected the glorious racing history. In fact, the price of the Italian precious metal was around 13,000 marks, twice as high as that of a comparable four-cylinder Honda CB 750.
A good quarter of a century later, another 750 four-cylinder with the glorious name is preparing to revive history. At 50,000 marks, the new F4 costs 2.6 times as much as the sportiest four-cylinder in the 750 class, the Suzuki GSX-R 750. And of course this MV also has to put up with the question of whether it lives up to its name and the comparison withstands the current competition.
At least in terms of attractiveness, the visitors to the Milan salon with their overwhelming presence at the MV booth voted unanimously for the new superbike, the design of which comes from a certain Massimo Tamburini. He has always had a strong relationship with the red and silver racers from MV Agusta: in the early 1970s, he modified the 750 S according to his own ideas.
At that time he was employed in a locally renowned heating company in Rimini whose name was composed of the initials of the three managing directors Bianchi, Morri and Tamburini zu Bimota. And the motorcycle enthusiast Tamburini founded out of enthusiasm and a lack of trust in Japanese chassis – he crashed in 1973 with a Honda 750 in Misano – a branch that is now world-famous. In the same year Bimota began to build exclusive chassis in small series as a replacement for the rather undersized Japanese chassis. But Grand Prix drivers such as Jonny Cecotto, Walter Villa, John Ekerold and many others also reaped the winning laurel with products from Rimini. In 1985 Tamburini switched to Cagiva / Ducati, and in 1993 Claudio Castiglioni asked him to take over the Cagiva Research Center in San Marino.
Talking about spectacular designs, he finally achieved international renown with the Ducati 916. He did not want to copy their line with the F4, but rather consistently develop it further in line with his design philosophy. Also striving for continuity and originality from a technical point of view, he combined a tubular space frame made of chrome-molybdenum steel with cast shares made of magnesium for the swing arm bearings for the Cagiva in-line four-cylinder. As with many ingenious constructions, however, the final consequence is missing: The mounting of the swing arm in the engine housing, as in some Hondas and Ducatis, would have saved the complex cast parts.
It is undisputed that many components are evidence of a high level of design effort. The special six-piston bend from Nissin are provided with three different piston diameters for even pad wear. The front wheel with the generously dimensioned, but thin-walled wheel axles rests in the quick-release fasteners of the 49er upside-down fork from Showa. Another special feature: The front tire of the unique size 120 / 65-17, specially produced for MV by Pirelli and Michelin, should offer the best compromise in terms of handling and damping, according to the developers. The rear suspension is also unusual: the single-sided swing arm made of magnesium with integrated chain shaft and eccentric chain tension is extremely light thanks to modern construction methods. Tea rear wheel also has an axle with an opulent diameter but thin walls. Comparatively tiny wheel bearings save space and weight. Even on closer inspection, it is noticeable that the designers literally struggled for every gram and every millimeter. The hand levers are cranked so that the expansion tanks for the brake and clutch can be placed lower. Good for the extremely flat windshield.
The attention to detail is also reflected in the adjustable footrests and levers, which, like the ellipsoid headlights and other technical details, are protected by numerous patents or utility models. All of this contributes to the extraordinary stylistic overall impression. And even if Suzuki’s GSX-R squeezes more power from the same cubic capacity and Yamaha’s new R1 with passenger equipment and a full liter cubic capacity undercuts the MV in dry weight by a whopping three kilograms – despite all its perfection, they cannot offer the charisma of the new MV.
D.his certain something has already driven 200 motorcycle freaks worldwide into normal madness. The limited first series "d ?? oro" for 1998 is already sold out. But even less well-heeled enthusiasts are not out of danger. The start of large-scale production is planned for 1999. Equipped with aluminum instead of magnesium parts, a single or biposto should then cost around 30,000 marks. Still enough for sleepless nights, right??

Engine technology of the MV Agusta F4-750

Claudio Castiglioni clearly formulated the objective for the new Cagiva engine at the beginning of development: The engine should be the most compact and powerful oven-cylinder in its class, just good enough for a future World Superbike machine. In fact, the unit that was created in Varese looks comparatively delicate with its housing covers wrapped tightly around the engine and the alternator behind the cylinders. But in a direct comparison, the Japanese developers are already ahead again with their latest creations. In contrast to the central drive of the F4, the trend towards the side drive of the camshafts saves overall width and friction by eliminating a crankshaft bearing. The design engineers with the gear shafts lying one behind the other did not take advantage of the possibility of short overall length due to gear shafts lying diagonally or directly on top of each other, such as in Suzuki’s GSX-R or Yamaha’s R1. However, the power plant stands out from the competition in two ways. With a bore of 73.8 millimeters and a stroke of 43.8 millimeters, it has the shortest-stroke design. With the following models, a stroke of 52 millimeters increases the working volume to 890 cm³. The most interesting feature of the construction concerns the arrangement of the gas exchange organs. In the cylinder head developed by Ferrari, the intake and exhaust valves are not placed in parallel in pairs, but in a radial position in the combustion chamber. However, the special configuration requires a complex valve train. The two overhead camshafts actuate the valves via conically ground cams and bucket tappets. The radial principle and the short-stroke design are good for large valve diameters and high peak speeds – and thus for high peak performance. The injection system should also take care of that. Cagiva specifies 126 hp as output and, at least in the series, has missed the target of being the best, an attribute that the new Suzuki GSX-R 750 with nominally 135 hp has given. In general, technology freaks, in addition to the cassette transmission and the radial head, would like further technical highlights such as gear-driven camshafts or a dry clutch, which underline the claim of an exclusive superbike even more clearly. Nevertheless, Superbike fans in general and MV fans in particular can hope that the engine of the F4 has the potential to build on the great successes of its predecessors.

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