AGO'S racer on the road

MV Agusta's exotic sports bikes of the Seventies offered a glimpse into the technology of two decades earlier. John Nutting tested a number of versions while at Motor Cycle newspaper.

BETWEEN 1966 and 1972, Italian star Giacomo Agostini won the 500cc world championship as he pleased, with no significant opposition. The MV Agustas he campaigned were nothing like the modern versions produced by the Cagiva group: they were pure-bred racers that had been developed over two decades and had acquired a reputation as exclusive, exotic, multi-cylinder machines that few people had access to. True, MV's seven-year winning streak, complemented by Ago's five 350cc titles from 1968 to 1972, resulted mostly from the other Italian factories pulling out of racing in 1967.
As an opportunity for MV Agusta to sell road bikes on the back of racing success it was as good as it gets. But it wasn't until 1969 that the Gallarate factory launched a sports bike, the 750S, and even then production versions were only available in small numbers after 1971. Today, the top motorcycle manufacturers develop road bikes alongside MotoGP and Superbike racing machines, squeezing every last drop of publicity from marketing campaigns.
Why MV's aristocratic family owners never made the decision to make their road bikes in bigger volumes we'll never know. But because MV Agusta road bikes were so rare and unattainable, they were that much more desirable. Few riders knew what they were like, and the exotic racing image was thereby further enhanced. So in 1973 when Chris Meek, then owner of the Mallory Park racing circuit, called the office of Motor Cycle with an offer to road test his MV Agusta 750S, I nearly bit his hand off, so to speak.
Meek filled the image of the archetypal MV owner: rich, flamboyant and keen for a bit of publicity. He'd spent upwards of £2000 on a motorcycle - much more than twice what you'd expect to pay for a top-of-the-range Kawasaki 900 - and as a businessman he no doubt wanted to get his money's worth out of it.
I was happy to oblige. With barely a year of road testing for the paper under my belt it was a chance not to be missed. And so started my relationship with a number of MV Agustas that plumbed the depths of frustration as much as climbing the heights of exultation.

Feast for the eye

Fully-faired 790cc 'America' was no better all round than the earlier 750S.THE 750S was a beautiful machine in every way. With a red-painted frame and supple red racing seat, huge blue-and-white fuel tank, lashings of polished aluminium and that iconic double-knocker four cylinder engine taking centre stage it was a feast for the eye. It sounded as if it came straight from the race track too, its four chromed exhaust pipes blasting out a symphonic chime that barely overwhelmed the mechanical chattering of the engine. To see and hear it was to be hooked. It felt right too.
Slim for a four, the 750S offered a well-balanced riding position with wonderfully smooth controls that showed care had been taken in their design. Clip-on handlebars had soft grips and sculpted levers. The alloy knurled footrests were set well back - unusual for the day - with short foot levers. Brakes were huge drums, the front using four leading shoes.
First impressions were a delight. MV Agusta first revealed the prototype of a four-cylinder road bike as far back as 1950. It was both stylish and novel with a parallelogram arrangement for the rear suspension and twin round headlamps.
It looked very similar to Gilera's pre-war supercharged racers because the design came from the pen of the same engineer, Reno Leoni. But it was never commercialised. It took another 15 years before MV sprung the first modern four, the portly 600 tourer with dual front cable-operated discs and shaft drive. Few were sold, and the first thing most buyers wanted to do was convert it into a sportster.
The 750S was a derivative of the 600 using a similar but overbored engine. Peak power of the 743cc (65 x 56mm) engine was 65 bhp at 7900 rpm: this was enough, said the factory, for an impressive top speed of 129 mph. The most novel feature of the motor was that it used a single casting to house the crankshaft and gearbox. Like the racing engines the crankshaft was a built-up assembly running in roller bearings. Likewise the one-piece connecting rods ran on needle rollers.
The crank assembly was then assembled into another casting that dropped into the top of the crankcase. Onto this, individual cylinder barrels were mounted to be topped by a one-piece cylinder head. Between the two middle cylinders a train of spur gears (carried in another casting) took the drive to the twin overhead camshafts. The valves, operating at what was then a typically wide 90-deg included angle, were opened by cam lobes that operated on inverted buckets. As with most of the engine, the valve clearance adjustment required careful stripping, measurement and reassembly for the best results.
'Lash' in the primary gear drive depended on the assembly of the crankshaft into the cases, which contained separate drives for the oil pump in the sump and the ignition distributor on the top of the gearbox. It was hardly ideal for mass production.
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