MV Agusta 125

MV Agusta 125 Two-shaft 1958

The first racing motorcycle built by the world's most famous four-stroke cycle manufacturer—MV Agusta—was a two-stroke single-cylinder 125 that had been derived from a production model. This motorcycle won several races during the years following World War II, including the 1948 Italian Grand Prix, which was run at the Bocche dei Canali Circuit in Faenza because the Monza track had been destroyed by bombing. It was at Faenza that the MV Agusta 125 had to face the competition of the Mondial two-shaft, four-stroke racer.

The formidable Morini company was also changing cycle, and MV Agusta decided to build a two-shaft gear engine. It generated 13 h.p. at 10,000 r.p.m. on its first test.
In 1950 and 1951 the MV Agusta technicians tried out various mechanical and aerodynamic solutions, but the MV 125 could not beat the Mondial. In 1952 the situation changed abruptly in MV Agusta's favor, and Ceyl Sandford found himself with a small MV that won him the world championship.

The following year the MV 125, with a little more horsepower than the prototype, was beaten by the NSU Rennfox, although it still won the manufacturer's prize.
The MV Agusta 125 was a winner at the world championship again in 1955, when it was driven by Carlo Ubbiali, the best racer of the NSU withdrew from racing and the new Mondial was not powerful enough. MV remained on top when it won the 1956 championship as well.

Six years after it was built, the MV 125 two-shaft was still substantially unchanged. The most important modification was in the transmission. In 1955 a sixth speed had been added. The design had been revised several times to make it more aerodynamic. The MV was helped by regulations that provided for something more like a two-wheeled torpedo than a motorcycle.

In 1957 Tarquinio Provini and his Mondial took the title away from MV, but the next season MV Agusta was ready to fight for the championship once more. Mondial followed NSU in withdrawing from racing, and Provini was taken on by MV as

Ubbiali's backup man. The 1958 version of the MV Agusta 125 had a new dolphin-style fairing that left the front wheel exposed. MV won, ahead of an unlucky but ambitious Ducati. MV owed part of its success to Carlo Ubbiali, who continued to win for two more years. In 1961 Phillis' Honda created major ch

Motorcycle: MV Agusta 125 Two-shaft Manufacturer: MV Agusta, Cascina Costa,
Gallarate Type: Racing Year: 1958
Engine: MV single-cylinder, four-stroke, with overhead two-shaft geared distribution. Displacement 123.5 cc. (53 mm. x 56 mm.)
Cooling: Air
Transmission: Six-speed block
Power: About 20 h.p. at 12,000 r.p.m.
Maximum speed: About 112 m.p.h. (with partial fairing)
Chassis: Double cradle, continuous, tubular. Front and rear, telescopic suspension
Brakes: Front, central drum, four shoes; rear, central drum

MV Agusta 125 1960

1960 MV. 125. Although the name "M.V." is almost inevitably I-1 thought of in connection with the four-cylinder racers, it must be remembered that this factory dominated all the solo classes, 125 ex., 250 c.c, 350 c.c. and 500 ex., in the World Championship for three years. The M.V. star performer on a "125" (and on a "250") was undoubtedly Carlo Ubbiali who, in i960, won his fourth 125 c.c. T.T. race. In this race, over the Mountain circuit in place of the Clypse course, he led from start to finish, heading his team-mates Gary Hocking and Luigi Taveri home at an average of 8560 m.p.h. He raised the lap record to 86-13 m.p.h. on the second of his three laps.

This race was held on the Monday of race week, marking the start of a new era in the T.T. history, with "125", "250" and sidecar races on the Monday, the "Junior" on the Wednesday and the "Senior" on the Friday of race week.

Cycle-wise, his machine was fairly conventional; the motor, too, showed little change from the same factory's "125s" of previous years. Built in unit with the gearbox, the engine had gear primary drive on the near-side and chain final drive on the opposite side. The cam-box of the d.o.hx. mechanism was a massive affair, and a huge "T"-shaped gear case enclosed the gear train drive to the shafts. On the outer cover of this case was carried an oil pump whence a maze of pipes led to numerous points of stress.

Exposed hairpin valve springs were used, and a skew gear drive from the end of the mainshaft operated the contact-breaker for the coil ignition. A couple of large castings just astern of the cylinder barrel looked like miniature ship's ventilators—they were crankcase breathers!

SPECIFICATION
Engine: single-cylinder 125 c.c. d.o.h.c; drive to
camshafts by gear train. Ignition: coil, with contact-breaker driven by skew gear
from engine drive-side mainshaft. Transmission: gear primary drive to unit construction
six-speed gearbox; final drive by chain. Frame: duplex cradle with pivoting-fork rear suspension. Forks: telescopic.

King of the "125s"—Carlo Ubbiali whips his M.V. over Quarter Bridge on his way to winning his fourth Ultra-Lightweight T.T., in i960.