MV Agusta 500 four-cylinder

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MV Agusta
MV 500 Corsa ST 76.jpg
MV Agusta 500 four-cylinder, model 1974
MV Agusta 500 four-cylinder
Manufacturer MV Agusta
Production period 1973 to 1976
class Racing motorcycle
Motor data
Four-stroke engine , air-cooled four-cylinder engine, DOHC with four valves hanging in the head operated by bucket tappets, oil sump lubrication, four Dell'Orto carburettors with a diameter of 32 mm, flywheel magneto ignition
Displacement  (cm³) 499.5
Power  (kW / PS ) 72 (98) at 14,000 min -1 (1973)
Top speed (  km / h) 285 (1973)> 300 (1976)
transmission Six-speed gearbox
drive Chain
Brakes front: double disc brake 250 mm / rear: 230 mm disc brake
Wheelbase  (mm) 1,360
Seat height (cm) ?
Empty weight  (kg) 120-128
Previous model MV Agusta 500 three-cylinder
successor none

The MV Agusta 500 four-cylinder (1973-1976) was a racing motorcycle from the Italian company MV Agusta , which was used in the top class of the FIM for the motorcycle world championship . With this motorcycle MV Agusta became world champion in 1973 and Phil Read became world champion driver in the class up to 500 cc in 1973 and 1974.

Development and technology

The most famous racing machine from MV Agusta, the three-cylinder or Tre , with which Giacomo Agostini won the world champion in the class up to 500 cc without interruption from 1966 to 1972, was just powerful enough in the 1972 season to withstand the newly emerging competition from two-stroke motorcycles from Yamaha and Keeping Suzuki in check. For the 1973 season, an existing four-cylinder from 350 cm³ displacement was drilled out to 433.5 cm³ displacement, which could achieve higher speeds than the three-cylinder. The power was specified with 88  PS (65 kW) at 14,000  revolutions per minute .

This almost corresponded to the performance values ​​of the old Tre , whose development was exhausted. Arturo Magni , race director and chief developer at MV, was unable to achieve the necessary stability with the narrower and lighter engine. Agusta's helicopter division under Dr. Ing.Bocchi, who previously developed twelve-cylinder engines for Lamborghini and Ferrari , was asked for help. Bocchi developed the engine further. The camshaft drive via gear wheels, previously on the side of the cylinder block, has now been arranged between cylinders 2 and 3, as with the series engines. The four-cylinder in-line has a width of 40 cm and a dry weight of 55 kg. In contrast to those of the series engines, the light metal cylinders are made from one block. The cylinder head, cast in one piece, has roof-shaped combustion chambers. The two inlet valves with a diameter of 20.5 mm and two outlet valves with a diameter of 16 mm are actuated via bucket tappets and closed with two barrel springs inserted into one another, the valve angle is 55 degrees.

Races

1973

At a displacement of 499 cc (stroke: 57 mm, bore: 49 mm) taken, the stable motor in the first '73 Version reached 95-98 horsepower at a speed of 14,000 min -1 . This enabled Read, who had had this engine available since the third race, prevailed over the two-stroke competition and became world champion. Agostini was in the motorcycle world championship 1973 , disappointing for him, only third in the world championship; he competed in the first races on the old tre . Initially, the four-cylinder was launched with just one brake disc at the front and size 3.00-18 tires at the front and, depending on the race course, 3.25–18 / 3.50–18 / 3.75–18 at the rear on spoked wheels.

1974

After the surprising departure of Agostini to Yamaha (he felt neglected towards his teammate Read) the four-cylinder was subjected to a further increase in performance. The '74 version of the 500cc four-cylinder reached at a speed of 14,500 min -1 an output of 108-110 hp. The drivers Read and Gianfranco Bonera (the second driver at MV Agusta) always complained about weaknesses in the chassis. A central rear wheel suspension was used ( Cantilever system ), another Ceriani fork was used and a rear wheel slick in size 4.50-18 was experimented with. Probably no other racing model from MV Agusta has chassis changes made so frequently. Nevertheless, Read managed to repeat his previous year's success in the motorcycle world championship in 1974, also due to technical failures of the powerful two-stroke engines. A decision by the FIM to reduce the volume of the racing machines to 116 Phon in the future  should be made in particular for the four-stroke engines from MV Agusta. Two-stroke engines were easier to dampen without sacrificing performance, as a revision of the resonance chamber was sufficient. Measured on the MV Agusta four-cylinder (74 and 75 version) between 125 and 130 Phon on the undamped exhaust pipe. Read and Agostini drove with earplugs to be able to endure the background noise.

1975

There was no increase in performance compared to the previous year's machine. A tubular space frame was installed instead of the old detachable double loop frame in order to achieve greater chassis stability. A wider swing arm was also used to accommodate the slick on the rear axle , which was driven for the first time . The 1975 motorcycle world championship was exciting right up to the last race, the Czechoslovak Grand Prix. The duel between Agostini ( Yamaha OW26 / two-stroke) and Read (MV Agusta / four-stroke) for the drivers' title was closer than it has been in a long time. In the penultimate race (Finland), Read's four-stroke engine suffered magnetic damage, the only technical failure of the season. Due to the cancellation results, Agostini only had to cross the finish line and score points in the last race; if Agostini had failed, Read would have become world champion again. Read won the last race with the four-cylinder, but Agostini finished second and thus for the first time world champion in the class up to 500 cc on a two-stroke machine.

1976

After the surprising return from Agostini to MV Agusta, the machine was revised again. "Ago" only had a two-year contract, and Yamaha officially retired from racing in late 1975; Read, previously the No. 1 driver at MV, switched to Suzuki. With the sponsors Marlboro and Api on the racing fairing, Agostini competed in the 1976 motorcycle world championship . The last version of the 500 series was specified with the performance data 115 HP at a speed of 14,500 min −1 . The new limit values ​​in terms of volume were met by this machine through a redesigned cylinder head and the first-time use of a rear silencer with 115 Phon.

The season was disappointing for MV and Agostini, and Agostini never made it onto the podium. The two-stroke engines from Suzuki were superior in terms of performance and meanwhile so stable that Barry Sheene became the undisputed world champion. On August 29, 1976, the last race of the season, Agostini managed to achieve the last race victory of a four-stroke engine in direct comparison with two-stroke racing machines with the MV Agusta on the drivingly demanding Nürburgring - Nordschleife . After 7 laps he crossed the finish line 52 seconds ahead of second, Marco Lucchinelli in Suzuki.

epilogue

After the last race at the Nürburgring, MV Agusta officially withdrew from motorsport. After 30 years of motorsport, the new majority shareholder did not want to invest any more money in the racing department of the financially troubled company. A fully developed 180 ° V-engine (as the successor to the in-line four-cylinder), similar to the König boxer , installed lengthways in the frame, was never used. It was not until 2002, after the ban on two-stroke engines in the premier class, that four-stroke engines were used again in the world championship in the newly created MotoGP racing class .

  • MV Agusta 500 (1974-75)

  • MV Agusta 350 (1976) identical paintwork to the MV 500

References

literature

  • Mario Colombo, Roberto Patrignani: MV Agusta . Motorbuch Verlag. Stuttgart 2000, ISBN 3-613-01416-5 .
  • Siegfried Rauch: Famous racing motorcycles. 2nd Edition. Motorbuch Verlag, Stuttgart 1980, ISBN 3-87943-590-1 .
  • Volker Rauch: Motorcycle World Championship 1975 . Motorbuch Verlag, ISBN 3-87943-389-5 .
  • Christian Spahn: MV Agusta . Technology and history of racing motorcycles. 1st edition. Serag-Verlag, 1986, ISBN 3-908007-13-1 .

Web links

  • motorsportretro.com various races as well as helmet camera from Read on MV 500 (accessed on September 29, 2011)

Individual evidence

  1. ↑ MV Agusta Club.de (accessed on September 28, 2011)
  2. ↑ Rauch, p. 164
  3. ^ Spahn: MV Agusta. 1986, p. 207
  4. ^ Spahn: MV Agusta. 1986, p. 232 ff.
  5. ^ Colombo, Patrignani: MV Agusta . 2000, p. 112.
  6. ^ Spahn: MV Agusta. 1986, p. 236.
  7. ^ Colombo, Patrignani: MV Agusta . 2000, p. 112
  8. ^ Spahn: MV Agusta. 1986, p. 236.
  9. ^ V. Rauch: Motorcycle World Championship 1975. P. 143.
  10. ^ Spahn: MV Agusta. 1986, p. 250
  11. ^ Spahn: MV Agusta. 1986, p. 255.
  12. ^ Colombo, Patrignani: MV Agusta . 2000, p. 113.