Gilera 500 Racer

Gilera 500 Story

In 1946 the Gilera company modified its old Grand Prix racer, eliminating the supercharger and mounting two classic carburetors. This was a purely palliative change and the results were rather disappointing. At the same time the racing department of the company was already working on a new four-cylinder model designed to compete with the British single-cylinder motorcycles. The British had an advantage at the time, because they had been refining nonsuper-charged motorcycles since the 1930s and now were in a position to dominate the most important international races.

The new Gilera motorcycle was ready in 1948. The engine still had four cylinders but the forward inclina-
tion was barely 30°. Its cooling system used air rather than water, and one carburetor fed two cylinders. Another difference was in lubrication. The oil tank was no longer separate but occupied a lower chamber of the engine block.
The chassis of the four-cylinder was still mixed, with tubular elements and stamped-plate parts. There were rear friction shock absorbers and a front parallelogram fork. The total weight of the vehicle was reduced to only about 290 pounds.
But this new creation of Gilera did not become an immediate success. Although it won regularly in Italian races, even up against the fine Guzzi two-cylinder, it was not consistently successful against the British competition, especially the AJS 500 Porcupine two-cylinder and the Norton Manx, with its single-cylinder engine derived from the famous 1936 International M 30.

By 1950 the Gilera four-cylinder had been brought to the peak of its racing capacity. At the close of the 1949 season, the Gileras turned in a dazzling performance at Monza. Nello Pagani and Arciso Artesiani rode the four-cylinders to win first and second place. As the Gilera star rose, the fortunes of Geoffrey Duke and Leslie Graham, racers of Norton and the 1949 AJS world champion, began to decline. Gilera did not win the championship in 1950. Nevertheless Gilera had the best all-round Vi-liter at the time, and Umberto Masetti won the racer's championship with it.
In 1951 the British champion Duke

won the title for Norton, but the credit was chiefly the racer's rather than the motorcycle's.
The following year brought important changes. More horsepower was added to the engine, along with four simultaneous carburetors, and the chassis and the aerodynamics were also improved. That year Gilera and Masetti both won their championship titles.

At the beginning of the 1953 season, Geoffrey Duke switched to Gilera. The British press called him a traitor, and Norton replaced him with the Rhodesian racer Ray Amm. Duke's move spurred the British team to work harder, and throughout the season Amm did wonders riding the Norton single-cylinder. But the combination of Gilera and Duke won the championship.
For three consecutive seasons Gilera and Duke were an unbeatable combination. They won the world championship in 1953, 1954, and 1955, as well as a host of other races.

In 1956 the MV Agusta 500 four-cylinder, designed by Remor (who had also worked on the Gilera) and ridden by the new British star John Surtees, took the championship away from Gilera. The following year Duke was out of racing after the first races of the season because of an accident. But Libero Liberati and Bob Mcln-tyre, the Scot, won the title for Gilera. They also won the 350 class for championship brands with a 350 four-cylinder that was exactly like the 500. At the end of 1957 Gilera retired from racing.

Gilera 500 1952

Motorcycle: Gilera 500 Four-cylinder Manufacturer: Moto Gilera, Arcore Type: Racing Year: 1957
Engine: Gilera four-cylinder, four-stroke, with two-shaft overhead geared distribution. Displacement 499.4 cc. (52 mm. x 58.8 mm.)
Cooling: Air
Transmission: Five-speed block
Power: 70 h.p. at 10,500 r.p.m.
Maximum speed: Over 160 m.p.h. (with bell fairing)
Chassis: Double cradle, continuous, tubular. Front and rear, telescopic suspension
Brakes: Front and rear, central drum, double cam

Gilera 500 1955

Motorcycle: Gilera 500 Four-cylinder Manufacturer: Moto Gilera, Arcore Type: Racing Year: 1957
Engine: Gilera four-cylinder, four-stroke, with two-shaft overhead geared distribution. Displacement 499.4 cc. (52 mm. x 58.8 mm.)
Cooling: Air
Transmission: Five-speed block
Power: 70 h.p. at 10,500 r.p.m.
Maximum speed: Over 160 m.p.h. (with bell fairing)
Chassis: Double cradle, continuous, tubular. Front and rear, telescopic suspension
Brakes: Front and rear, central drum, double cam

Gilera 500 1957

1957 JUBILEE-T.T.-WINNING GILERAS. In 1957 tlie Isle of Man T.T. races celebrated their Golden Jubilee, and to Bob Mclntyre went the distinction of winning both the Senior and Junior races on Italian four-cylinder Gileras, the first time a foreign factory had completed a "double" in the major races.

On the Monday of race week Bob had led the Junior event on the first lap, but had to stop for a plug change at the end of the second, letting Dickie Dale (Guzzi) and John Hartle (Norton) get ahead of him. At the end of the third lap Bob was less than a minute astern of Dale, with Hartle betwixt them, but cruel luck gave him the lead again without undue effort, for both Dale and Hartle were brought down by an oil patch in the Quarry Bends. Then it was all over bar the shouting, with a victory at a record 9499 m.p.h. and a new lap record, on lap 1, of 97-42 m.p.h.

If Mclntyre did well in the Golden Jubilee Junior T.T. he did better in the Senior race, for he raised the lap record to over 100 m.p.h. for the first time (he topped the "ton" four times), setting it at 101-12 m.p.h. He led the race from start to finish, beating then-young John Surtees (M.V.) by a couple of minutes.
The Gileras he used in both races were near-identical apart from engine sizes and were, of course, direct descendants of the machines on which Geoff Duke scored his fabulous run of victories in the middle fifties. Both employed the "dustbin"-style streamlining then allowed in international road-racing.

The engine-gear unit was very similar in conception to its ancestor, the pre-war supercharged model, but the unit (without a "blower", of course) had air cooling and had its bank of cylinders only slightly inclined. It retained the gear-train drive to the overhead camshafts between the inner cylinders. This unit had first appeared (as a 500) in the Island in 1951, but it was not until 1955 that it

SPECIFICATION
Engine: four-in-line mounted transversely and inclined forward; 500 c.c, double o.h.c; drive to camshafts by gear train between inner cylinders.
Ignition: Lucas magneto.
Transmission: gear primary drive to unit construction five-speed gearbox; chain final drive.
Frame: duplex cradle with swinging-fork rear suspension.
Forks: hydraulically damped telescopic.