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Motorcycle Investor mag

Final Fling

(by Ian Falloon, Apr 2022)

MV Agusta
850ss

MV Agusta’s 850 SS Monza was the last hurrah for the legendary America platform

Between 1952 and 1976 MV Agusta dominated the world of Grand Prix motorcycle racing. Their formidable record included 270 World Championship races, 38 riders’ championships and 37 manufacturers’ championships but by the end of 1976 the company was in trouble.

On the racetrack their air-cooled four-strokes were no longer competitive against the liquid-cooled two-strokes. The factory racing department closed and MV Agusta’s expensive street bikes languished in showrooms. Rumours emanated about a merger with Ducati and MV motorcycle production moving to Bologna.

The 750 America of 1975 was meant to be MV Agusta’s saviour. Jim Cotherman and Chris Garville of the Commerce Corporation in New York persuaded MV’s directors the future lay in the US and optimistically predicted sales of 500 750 Americas a year. Although the America cost more than $6000 (three times that of a Kawasaki Z1) Cotherman and Garville gambled on an expanding market for luxury consumer goods.

Unfortunately they were a few decades ahead of their time and Americans weren’t ready for such a motorcycle. The 750 America was a sales disaster and two years later new unsold stock still remained at the factory.

Although MV was no longer building motorcycles, in 1977 long time factory racing team manager Arturo Magni was requested to convert some of the remaining America stock into the 850 SS.

MV’s four-cylinder engine had been pensioned off in 1966 as a racing design, and while no longer at the cutting edge of technology the venerable four was still a formidable and impressive unit. A train of spur gears drove double overhead camshafts and along with the pressed together roller bearing crank was supported in the sand-cast crankcase by a substantial rack.

The engine may have started life as a 500 Grand Prix design but it was intrinsically strong enough to cope with nearly double its original capacity.

Magni had prepared racing fours for multiple world champions, in particular John Surtees and Mike Hailwood, and knew these engines inside out. He enlarged the cylinder head ports and installed 69mm pistons, up from the America’s 67mm. The compression ratio was claimed to be 9.5:1 but was probably higher.

The individual barrels were thinner than on the America and with the standard 56mm stroke the displacement was 837cc. The 850 SS had the largest capacity factory-produced production four-cylinder engine, and it was also the most powerful, producing an estimated 85 horsepower at 9500 rpm (with some claims of 95 horsepower).

Much of the power increase was due to the installation of two America inlet camshafts (another inlet replacing the exhaust), a set of four unfiltered Dell’Orto VHB 27A carburettors, and four open chromed mufflers. Other features unique to the 850 SS included a dual-point Marelli 7K distributor providing a reduced dwell angle, allowing the coil to charge more quickly at higher rpm.

The 850 SS chassis was ostensibly that of an America and arguably compromised for full sporting use. Like the America the final drive was by a shaft, with a heavy crown wheel and pinion, and the frame was tall to allow cylinder head removal with the engine in situ.

With a dry weight of 230kg the 850 wasn’t exactly svelte. But while many Americas left the factory with Borrani wire wheels and leaking Scarab brakes the 850 SS had a set of EPM cast alloy wheels and superior Brembo brakes. The 38mm Ceriani front fork and Sebac shock absorbers were straight from the America.

The 850 SS, or Monza, wasn’t a bike you could see on display at the local dealership in 1977. This was a limited-edition motorcycle only available on special order to the few that could afford it.

By the time the 850 SS Monza appeared MV was about to close its doors, leaving the model as something of an enigma. Undeniably exclusive, because it retained the shaft final drive it didn’t offer significant functional superiority over other modified Americas with a Magni chain drive conversion.

The Monza may have been a pragmatic response to liquidating unsold stock but it was the end of the era for MV’s racing four.