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Motorcycle Investor mag

MV Agusta 750 S

(by Ian Falloon, Apr 2022)

The strange development tale behind a legend

With many human creations there is often a vintage period or vintage year, the time when a product represented a pinnacle of purity for design and function. The products of these vintage years soon earn a reputation, become surrounded by an aura and mystique, either justified or misguided, and are elevated to levels beyond their brethren. With Italian motorcycles one vintage year was 1974.

This year saw the end of MV Agusta’s dominance in Grand Prix racing, and the end of pure sporting motorcycles built without regard for legalisation and economics. After 1974 all motorcycles had to meet increasing noise and emission requirements, and they had to incorporate a left-side gearshift to be able to be sold in the US.

No longer were taillights small and discrete and motorcycles unencumbered by turn signal indicators. Carburettors had to breathe through restrictive air cleaners and exhausts become larger and quieter.

As manufacturers sought to increase sales motorcycles also began to follow trends of fashion. Heavy cast alloy wheels replaced the wire type with Borrani alloy rims, electronic ignitions replaced points, and there was a general increase in complexity. For many, it was a downward slide as motorcycle design was compromised to accommodate these new requirements.

When MV Agusta pensioned the 500cc Grand Prix four cylinder at the end of 1965 in favour of a new triple, the racing four was put into limited production as the 600. Count Agusta was determined that none of his production bikes would challenge his racers so the engine was enlarged, detuned, and provided with a shaft final drive.

He was certainly successful, and the 600 was as far removed from the race track as could be imagined. If any bike had a case of the uglies this was it. A huge rectangular headlight dominated the frontal aspect and it was slow and heavy to boot.

But what couldn’t be disguised was the magnificent four cylinder engine with straight cut gears driving the double overhead camshafts. Designed by Piero Remor back in 1949 the sand-cast crankcase was a one-piece casting, and the crankshaft and big-ends were all supported by roller bearings.

The widest part of the MV engine was the outer cylinders and in the adaptation to street use a generator and electric starter were positioned at the rear of the engine underneath the swingarm pivot, both driven by one-way rubber belts. The racing design could spin safely to 9000rpm, but the carburetion was by a pair of tiny Dell’Orto UBF24mm carburettors more suited to a 250. The result was an unremarkable 52 horsepower at 8200rpm, barely enough to power the 221kg 600 to 170km/h.

Count Agusta died in 1971 and without his opposition the 600 evolved into the sporting 750 S. The bore was increased to 65mm, retaining the 56mm stroke, and although it retained the small carbs the power went up to a claimed 65 horsepower.

But the 750 S was a much more appealing piece of kit. With a large 230mm Grimeca double sided shoe front brake instead of the weird cable operated Campagnolo disc brakes on the 600, and a beautifully sculptured fuel tank complemented by a red seat, the 750 S looked the business. But it still failed to deliver. The power claim was unduly optimistic, and no matter how good the drum brake looked it wasn’t really up to the task of repeatedly slowing the heavy MV.

All that changed for 1974 when MV decided it was time to create a real high performance sporting motorcycle out of the 750 S. They installed new cylinder heads with hotter cams, larger valves, and higher compression (10:1) pistons. With four Dell’Orto 27mm VHB square-slide carburettors breathing through open bell mouths, and four virtually open mufflers the power went up to 75 horsepower at 8500 rpm.

The true essence of the four-cylinder Grand Prix racing MV was finally replicated. Although the chassis was much as before a pair of 280mm Scarab discs replaced the front drum brake, and while not perfect they were a vast improvement. No Italian sporting motorcycle of the day was complete without a set of 18-inch light alloy Borrani wheels. The only criticism that could be levelled at the MV’s chassis was the choice of a skinny 35mm Ceriani front fork.

The details of the MV 750 S met every expectation for a high-end product. Weight saving didn’t really enter into the equation so there a noticeable absence of plastic components. The battery covers were pressed steel, the mudguards stainless, and the headlight holders and instrument panel forged aluminium. Chrome-plating predominated and instead of a plastic steering damper knob this was hand-knurled aluminium.

The MV 750 S represented the end of the pre-plastic era and it was a motorcycle built to last. It was also basically unaffordable and unobtainable. Fewer than 200 were produced and those available in Australia sold for $4700 at a time when a Ducati 750 GT could be had for around $1500.

After 1974 MV Agusta was lured into modifying their four for the American market. In some respects the next generation 750 America was superior (the 38mm front fork was a definite improvement) but the engine was detuned, and fashion predominated over function. Financial problems saw the company absorbed into an Italian Government conglomerate resulting in dubious matt black paint replacing chrome and plastic replacing aluminium. Compared to the hand finished 750 S the detailing on the America looked tacky.

Although the MV went well and handled adequately the riding experience wasn’t quite up to the legend. This was a motorcycle dominated by the engine, the sound of the gears whirring and the open exhaust intoxicating. Agile enough, due to the short 1420mm wheelbase, the weight of the shaft drive was considerable and the 35mm fork didn’t quite provide the surety that was evident with a Ducati Super Sport or Laverda SFC.

But the engine was undoubtedly stronger than those other Italian stallions, and the presence exuded by the MV unequalled. The bright red, white and blue paint and red seat sent an unsubtle message that this was the only motorcycle available with a 37 World Championship heritage.

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