Ondial 250 Bialbero
Racing Bikes ondial 250 Bialbero | |
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FB Mondial 250 Bialbero
When Mondial decided to retire the 125 two-shaft model that
had dominated racing during the years between 1948 and 1952, there was a
replacement waiting in the wings. The new Mondial 125 showed its derivation from
the old model. It was not that the old 125 had been outclassed by the MV Agusta
but that the resources of its engine had been poorly tapped, leaving much of its
potentiality undeveloped.
Mondial's designers and technicians concentrated on details.
The new engine that they came up with looked quite different from the old one,
but it had the same displacement (with the same bore and stroke), two-shaft
overhead bevel gear distribution, and only slightly more power17 h.p. instead
of 15 h.p. The crankcase was different and now held the lubricating oil. The
chassis had been redesigned and now had front and rear telescopic suspension in
place of the front and rear elastic suspension that had been used on the older
model.
The new Mondial 125 two-shaft also had a new rider in its
saddle. Tarquinio Provini replaced Carlo Ubbiali, who had switched to MV Agusta.
The new motorcycle won several races in 1954, and in 1955 it won the Italian
championship. There were epic duels that year between the Mondial and Agusta
companies in the world championship. The Mondial got better and better but
failed to win the championship despite its valiant efforts.
The engine of the Mondial 125 had not been sufficiently
modified. While it had enough horsepower it did not utilize the power well. The
problem was to get more out of the engine instead of trying to find another one
that might not be as reliable. A five-speed transmission had been installed, and
the overall fairing made the Mondial 125 look more like a record racer than a
Grand Prix racer.
In 1957 Provini, a fierce rival of Ubbiali, had a Mondial 125 that represented a
final synthesis of all the company's experiments with the engine since 1948. Now
the MV Agusta and the Mondial were on a par with one another. It was all up to
the riders.
Ubbiali won the first championship race that season. Provini
won the second, third, and fourth races of the season. Taveri, riding an MV, won
the fifth race, and Ubbiali came back at Monza to win the sixth and final race
of the championship. Mondial had won three and Agusta had won three. The
championship was given to Mondial in 1957 because its better placings in the
races it lost carried sufficient weight to break the tie in that company's
favor.
While the 125 was being developed, Mondial was also working on
a 250 model. After the 125's success in the 1955 Italian championship, the
Mondial people built a larger version of that model. But they immediately put
into the works a 250 two-cylinder, with two 125 engines. This solution provided
35 h.p. at 10,000 r.p.m. But the motorcycle was a failure. It weighed over 300
pounds.
Mondial returned to the single-cylinder formula, this time with full
displacement. The new motorcycle that resulted looked like Provini's 125 on the
outside, but the engine was quite different. The bore-stroke ratio reflected a
very flat engine, and the two-shaft overhead distribution had gears instead of
the bevel gear shaft.
In 1957 the Mondial 250 single-cylinder was raced by Provini
and Ceyl Sandford. It was Sandford who rode the 250 to win his second world
championship. (He had won his first world championship in 1952 in the 125 class,
riding an MV Agusta.)
Motorcycle: Mondial 250 Manufacturer: F. B. Mondial, Milan Type: Racing Year: 1957 Engine: Mondial single-cylinder, four-stroke, with two-shaft overhead geared distribution. Displacement 249.1 cc. (75 mm. x 56.4 mm.) Cooling: Air Transmission: Five-speed, six-speed, or seven-speed block Power: 29 h.p. at 10,800 r.p.m. Maximum speed: Over 135 m.p.h. (with full fairing) Chassis: Double cradle, continuous, tubular. Front and rear, telescopic suspension Brakes: Front, central drum, double cam; rear, central drum