The bike
In the mid-1950s, MV Agusta was alive
with innovation. Its first 500cc Grand
Prix title was just around the corner and
the Italian manufacturer was challenging
for titles in the smaller classes when the
factory displayed the MV 300 Bicilindrica
at the 1955 Milan Motorcycle Show.
This exciting all-new twin was
designed to compete with the Gilera
B300, but looking back, it seems MV
had taken a gun to a knife fight. Gilera
had been on a roll since taking the
500cc world title in 1952 with its double
overhead cam inline four. Late that year
it had debuted what it described as a
sporting twin, the 305cc Gilera B300.
Sure, the B300 had its cylinders inclined
forward a rakish 10 degrees, but the rest
of the specification was fairly mundane.
Unit construction of engine and gearbox
was a big step forward, but the engine was a low-compression,
single-cam, two-valve-per-cylinder workhorse that wasn’t with-
out issues.
Owners of early B300s complained of overheating engines
and main bearing failures. Improvements were made and the
model lasted until 1964, but it wasn’t a world beater.
Nevertheless, MV recognized that Gilera was weaning Italian
riders away from single-cylinder motorcycles, so it decided
to bring in a big gun and mount a challenge. That big gun
was Carlo Gianini, the man who had designed the 4-cylinder
Gilera Rondine in the 1930s. One of the
most powerful motorcycles of its era, the
Rondine developed nearly 90 horsepow-
er and set the 1937 world speed record
at 171mph (275kmh).
More recently, Gianini had worked
with Moto Guzzi to create its inline
4-cylinder rival to Gilera and MV in 1952,
which was raced until 1954. The engine
was mounted longitudinally and origi-
nally fitted with rudimentary fuel injec-
tion. However, shaft drive and an overly
complex design blighted its potential for
GP race success.
Nevertheless, Gianini was still the
go-to man for new designs, and Count
Agusta came knocking. The result was a
technically stunning engine, especially
compared to the rather mundane Gilera B300. Unit construc-
tion of the engine and 4-speed gearbox formed a solid basis,
but after that things got decidedly different.
Unlike most parallel twins of the time, the MV 300B’s cylin-
ders were separate castings, set far apart to encourage air flow
to achieve the best cooling. Sandwiched between them was a
central tower of gears driving the valve actuation.
The electric starter was bolted to the rear of the transmission,
and to keep the engine as narrow as possible the clutch was
driven from a gear cut into the crankshaft, and the generator,The 300B’s overall
styling was similar to MV’s
Tourismo Rapido, but the
300B had a unique frame
and Earles fork front end
(below and facing page).