1971 MV AGUSTA 750S
by Ian Falloon
There is no more hallowed name amongst the Italian motorcycle marques than that of MV Agusta. The testimony of this is in the total of 38 individual riders World Championships and 37 manufacturers World Championships over the twenty five year period from 1952 until 1976. During that time MV’s won a total of 270 World Championship races, an astonishing feat unlikely to be repeated ever again. The spin-off from this racing was a limited number of street bikes in a range of capacities, most notably the magnificent 750 Sport.
The first four cylinder MV Agusta street bike appeared in prototype form at the end of 1950, less than a year after the 500cc four cylinder racer made its debut. Count Agusta had persuaded Arturo Magni and Piero Remor to leave Gilera and the new engine was virtually identical to the Gilera design, so, in order to appear different the initial version incorporated shaft drive and torsion bar suspension. These features were also on the road going prototype, the R19 Turismo, but it never entered production.
Fifteen years later another prototype road bike appeared at the Milan Show, this time with a 600cc version of the same engine producing a claimed 52 HP at 9000 rpm. A certain amount of skepticism arose as to whether it would ever go on sale and to everyone's surprise 20 bikes were made in 1967. "Cycle" magazine tested one with the comment that it had "a bad case of the uglies" and it was generally agreed that this was one of the ugliest bikes ever to come out of Italy. It was obviously constructed as a touring machine so that customers wouldn't be tempted to convert one into their own four cylinder MV racer. Being 600cc with shaft drive and a dry weight of 221kg this was clearly impossible.
Despite the rather unfortunate styling, the 600 was really quite an innovative machine. It was one of the first across the frame fours and also one of the first to offer electric starting. It featured Campagnolo twin front disc brakes (cable operated and which were totally ineffective) and shaft drive. The engine was (apart from the capacity) identical to the Grand Prix fours of the 1950's complete with straight cut timing gears to drive the double overhead camshafts and a pressed up roller bearing crankshaft. Such an idiosyncratic and expensive machine had a very limited market and only 135 600's were sold between 1967 and 1972. It made way for the 750 S, a much more sporting motorcycle and more appropriate to represent the marque.
The prototype 750 S
Although Count Domenico Agusta had initially sanctioned only a touring 600 four cylinder for production, slow sales and pressure from dealers saw him reluctantly agree to the creation of a 750 Sport. But he was still resistant, fearing a 750 may not perform to expectations in competition so he insisted on retaining the shaft drive. And while the 750 now had four carburetors these were still the small 24mm Dell’Orto. A 750 S prototype, built out of a 600 was shown at the 1969 Milan Show but it was still some time before the 750 S went into limited production. The show prototype was very striking styled as a sports machine and as expected was the star of the show. The claimed power was 65 horsepower at 7,000 rpm, the top speed 225 km/h, and the price 1.950.000 lire.
Only nine 750 Sports were built in 1970, and this scenario may have continued if Count Domenico hadn’t died suddenly on February 2 1971. His brother Corrado succeeded him and initially there were few changes. The racing program continued unabated but the impediment allowing a production sporting four-cylinder MV Agusta no longer remained. As a result 56 750 Sports were built in 1971, with 28 sold in Italy, including the example under consideration here. All but two were built between August and December 1971.
Engine Number 214-014 | Frame Number 214015
THIS BIKE’S HISTORY
The MV Agusta 750 S under investigation here has a fully documented history from the date of manufacture on August 31 1971. One day later, on September 1 1971, it was delivered to the Alberto Pederzani in Milan, Italy. Pederzani was a personal friend of Count Domenico Agusta who had died eight months earlier, in February 1971. While sold through dealers in other parts of Europe, in Italy the early 750 S was only available to those known to Count Agusta.
Shortly after delivery this motorcycle was returned to factory for the installation of a 250mm magnesium Fontana front brake and machined forks sliders. The chassis and bodywork were also upgraded. A new steel fuel tank replaced the standard fiberglass type, a lower 1970 seat replaced the 1971 type, and an earlier Inox front fender was fitted. The final modification was a factory racing type fiberglass full fairing. Eugenio Carelli of Turin bought this 1971 MV Agusta 750 S in 1998 from Alberto Pederzani. In 2014 this motorcycle was advertised world wide and sold to Stuart Parr in NYC.
The registration is for Milan.
Automobile Club'Italia registration dated 2014. Here it dates the second sale as September 17 1998.
In 1998 this motorcycle was registered with Automobile Club d'Italia to Eugenio Carelli.
The second owner is documented as Eugenio Carelli of Turin.
The engine and frame number match the official factory records.
The mileage is undoubtedly correct.
“There is no more hallowed name amongst the Italian
motorcycle marques than that of MV Agusta.”
Initially the 750 Sport engine was derived from the 600, but with a new number sequence beginning at 214-001. 1971 engine numbers went from 214-010 to 214-075. As with the 600 all the engines were individually built, with each component selected for a perfect fit. This was probably the reason why so few 750s were built compared to 350 twins during this period.
CRANKSHAFT, CRANKCASE, AND CAMSHAFT DRIVE
On the first 750 series the crankcase castings were similar to the 600 and featured a 15-fin sump. The crankshaft still included a 56mm stroke and helical primary gear, but had larger (19mm) journals at each end. In other respects the crank was as for the 600, with the same con-rod and big-end dimensions. The primary drive was still 1.75:1 (56/98). The crankshaft rack was new (to accept the larger cylinders) and the 12 studs retaining the crank in the rack increased from 8mm to 10x100mm. This required new crank underneath “U” fittngs. The crank rack design was similar to the 600 as it still didn’t include a rib. The crankcase also retained an inspection plug on the right. Other similarities with the 600 included the narrower 9mm camshaft drive gears.
Also shared with the 600 was the smooth faced crankshaft rack and inspection plug.
The early 750 S cylinder head was also based on the 600
The early 750 S cylinder had two outer horizontal fins with a cutaway for the spark plug
CYLINDERS, pistons, CYLINDER HEAD AND CAMSHAFTS
The full circle 65mm three-ring Borgo pistons were similar to those of the 600 but were now forged and provided a compression ratio between 9.3:1 and 10:1 (depending on the data provided). Early factory data indicated 9.3:1 while the Owners’ Manual of April 1972 stated 10:1. The piston weight was increased slightly over the smaller 600 pistons, to 200 grams. Unlike the 600, the 750 had 1.68x69.57mm O-rings installed underneath cylinder base gaskets.
A new cylinder head was produced for the 750 Sport but this was initially based on the 600 (with two horizontal fins) and modified combustion chambers. The included valve angle remained at 80 degrees and the valves identical (29.4mm inlet and 28mm exhaust) with the same 32 and 30mm valve seats. The outer fin was still cutaway around the spark plug. The camshafts and valve timing were also the same as the 600. The valve adjustment system was new for the 750, with the adjustment shims now underneath the bucket instead of on top as on the 600. This solution was more suited to high performance but to replace shims to adjust the valve clearance required removal of the camshaft. The early valve buckets were the two-hole type, similar to the 600, and prone to cracking. The 750 also received new inner and outer valve springs.
The cylinder head and cylinders were still bolted to the crank rack (without a rib) with 12 waisted studs. These were now 10x169mm and included extended spacers to the bottom of the stud counter bore holes to prevent the stud shearing spacers at the top. The retaining nuts were still external hexagonal 9mm. The 600-style crank rack provided a smooth look to the engine but according to Dave Kay, “It was always a mismatch”.
carburetors and exhaust
Although the 24mm cylinder head intakes and manifold stud arrangement was carried over from the 600, instead of two Dell’Orto carburetors on siamesed manifolds the 750 featured four individual UB 24 B2 and UB 24 BS2 carburetors. These still breathed through open aluminum bell mouths and a single cable operated a lever from the center. The exhaust ports were threaded as before, but with four individual chrome-plated header pipes and seamed mufflers. An unusual feature was the exhaust system was hung on the bike with the frame drilled afterwards for mounts. This was a satisfactory solution for a new machine but made fitting replacement exhaust systems difficult.
Early MV 750 Sports had four seamed mufflers.
Dell'Orto UB 24mm carburetors with lever-operated throttles.
Threaded exhaust ports.
IGNITION and electrical System
The single point Bosch JF-4 distributor and Bosch Dynastart was identical to the 600, but for the 1971 750 S the battery was upgraded to 32 Ah. The spark plug leads were changed to red during 1971.
The fiberglass side cover is probably aftermarket because the grill mesh is much finer than standard.
gearbox, clutch, and final drive
The 1970 750 S had a similar gearbox to the 600 but was improved for 1971. Previously only first gear was manufactured integrally with the mainshaft but now the mainshaft included first and second gears. The fourth gear on the mainshaft was also new but the layshaft and other gears were unchanged. Apart from a direct 5th gear the ratios were unchanged.
The 750 S also had a new clutch, now with 7 driven plates (3mm) and 7 steel driving plates. These were the same as on the 600 but the driven plates had a different clutch center, with triangular inner teeth. Clutch actuation remained as for the later 600, with 3 rods and 3 balls as did the 5 clutch springs. The clutch primary gear was also new, the unchanged clutch basket still riveted to it.
Although the intermediate bevel gear ratio was unchanged, for 1970 the 750 S final drive was raised to 2.54:1 (33/13). This was obviously a little high, blunting top gear performance so the ratio was lowered slightly during 1971 to 2.67:1 (32/12).
FRAME, WHEELS, TIRES, BRAKES, and suspension
The 750 S frame was similar in design to the 600, but painted red with numbers beginning at MV4C75 214001. Early frames didn’t have an Italian frame homologation number but during 1971 and 1972 the frames included DGM and OM stamps but no number. The frame also held the large diameter engine breather hose, this connecting to the breather outlet near the distributor housing, running through a hole near the steering head and exiting through a hole in the tube underneath the motor. The steering head angle was 63° from horizontal (27° from vertical) and the headstock length 160mm.
Frame differences to the 600 included a center stand with looped feet and a rounded rear sub frame, associated brackets and a different bolt-on battery support (for the larger battery). Borrani aluminum 2.15x18 inch wheels were still fitted front and rear, but the suspension was also new. The Ceriani fork had polished alloy legs and exposed 35mm tubes. The rear suspension was by a pair of BREV Sebac 259032 320mm shock absorbers, with chrome springs. The shock bodies were painted red and the lower spring collar included an adjusting handle.
A Fontana 250mm front brake was also fitted by the factory. Both shoe plates and the hub were magnesium, with cast-iron ring inserts. Built by Daniele Fontana in Milan, this four-leading shoe brake was a work of art and designed for large displacement F750 bikes. It featured on the F750 MV Agusta racer Giacomo Agostini rode in the inaugural Imola 200 race in April 1972.
Sebac shock absorbers were standard.
Borrani WM3 aluminum wheel rims
TANK, SEAT, AND FAIRING
Along with a factory full fairing, factory modifications included fittng a steel fuel tank and the1970 lower profile seat.
SUMMARY
With three verified owners, this MV Agusta 750 S (engine number 214-014; frame number 214015) comes with impeccable provenance and known history from the day of manufacture. The engine and frame numbers correspond perfectly with the official factory records and the speedometer reading of 21,037 kilometers is undoubtedly original. Shortly after delivery it was returned to the factory where a new tank, seat, fairing, racing Fontana front brake and an earlier front fender were fitted. The condition is as expected for an unrestored, moderately used 50-year old motorcycle. Thus it isn’t presented as concours but with some patina. With very few manufactured, the early (1970 and 1971) MV Agusta 750 S is extremely rare. And in this original unrestored condition it is even more so. The inclusion of a factory-supplied fairing, tank, seat and racing front brake only strengthen the appeal of this particular example.
This is surely one of the most desirable examples in existence of an already rare species.
REPORT BY: IAN FALLOON
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