Italian Grand Prix Motorcycles: A Review
ITALIAN GRAND PRIX MOTORCYCLES: A REVIEW
BIANCHI TWIN was originally conceived in 1961 as a two-fifty (55mm × 52mm) with 40 hp @ 12,000 rpm), but due to its bulk it was converted to a 350 by enlarging the bore to 65mm while retaining the same stroke. Power was stepped up to 53 bhp @ 10,800 rpm. As a 350 machine proved quite successful, it was then enlarged to 500cc in another version. In this form its bore/stroke was 70mm × 59mm = 452cc; it developed 60 bhp @ 10,000 rpm. Over twisty race courses this machine was a match for the big fours since it was lighter and handier, and as a matter of fact it beat both the MV and Gilera fours at Sanremo and Imola. For 1964 it is being brought out closer to the capacity limit of its class to gain more horsepower; 67 bhp is the forecast. Double overhead cams are driven by a spur gear in the center of the crankshaft which also drives the distributor and oil pump. The six-speed gearbox is in unit, wet-sump lubrication is used, and weight is 281 pounds for the 350 and 286 pounds for the 452cc.
AERMACCHI is the only "over the counter" bike built today in Italy. It is offered in either 250 or 350 versions, the latter of which, if rumor serves its task well, will be seen in the U.S. very soon. Both are particularly attractive to the "private" (ie; non-factory supported or sponsored) rider, as they are not expensive and are easy to maintain. The 250 delivers 29 hp @ 9,800 rpm at the rear wheel, while the 350 gives well over 30 bhp @ 8,500 rpm. Bore and stroke are 72mm × 61mm = 248cc, and 74mm × 80mm = 348cc. Both are push-rod operated ohv, have five-speed gearboxes in unit with the engine, coil ignition, and 18-inch wheels. A new high resistant steel rod is used this year. More details can be found in CYCLE WORLD, December 1963 issue.
MORINI 250 is the miraculous single that challenged and beat the multi-cylinder machines in 1963's world championship events ridden by Tarquinio Provini. It is surely the fastest single-cylinder racer of today, even outrunning the Norton 500cc Manx and the Matchless G-50. Launched at the 1958 Italian Grand Prix, which it won, this 72mm × 61mm bore/ stroke, gear-driven dohc machine puts out 36 bhp @ 10,500 rpm, transmitted to the rear wheel through a six-speed gear box in unit. Its superiority lies in its lighter weight, 231 pounds, better torque and handling than its rivals, plus the superior Provini of course. Double-coil ignition, wet-sump lubrication, gear-driven primary drive, dry multi-plate clutch, 18-in wheels.
CARLO PERELLI
BENELLI 250 FOUR, introduced in 1960, was built on the lines of a similar model (but water-cooled and supercharged) developed just before the outbreak of World War II. It is showing great promise but still has teething problems. Scheme of the power plant follows Italian tradition with cylinders set transversely across the frame; double overhead cams are driven by a set of gears between the cylinders, primary drive is by gears between the two middle cylinders. Bore and stroke are 44mm × 40mm, power output is 40 hp @ 12,500 rpm. Other details: Coil ignition, six-speed gearbox in unit with the engine, wet-sump lubrication, 241 pounds weight, and 18-inch wheels.
ITALY IS WORLD KNOWN as the country of lightweight motorcycles, yet oddly enough, its present grand prix racing bikes are only of the medium and large capacities. Gone are the 100cc and 125cc Ducati desmodromics, the 125 and 175 Mondials, the 125 MV (all double overhead cam machines that achieved immense success in the fifties). Little interest exists in the 50cc class in Italy, but the fabulous Gilera "Fire Engines" have remained in the 250cc and 350cc classes, and in the 500cc class in 1963, keeping alive the glory of the Italian motorcycle industry and its sporting traditions that date back to the first years of this century.
In the early thirties a team of engineers from Rome, including the famed driver/designer Piero Taruffi, developed a 500cc four cylinder racer called a "Rondine" (Swallow), which was bought in 1936 by the GILERA concern of Arcore (Milan), to be raced under their name. It won the European Championship in 1939. Brought up to date after the war, it lost the supercharging and water cooling of the first version, but the general layout of the power unit remained unaltered (later to be copied by several Italian and Japanese manufacturers). The 500cc Gilera was indeed the most successful multi-cylinder mount used in 1946-47. At the end of 1957 Gilera retired from racing, only to return again with the same machinery in 1963 with the famous Scuderria Duke. The Arcore "Fire Engine" with its 45° inclined cylinders, 52mm × 58mm bore/stroke dimensions, develops 70 bhp @ 10,500 rpm, has dohc that are gear driven (as is the primary drive), magneto ignition and five-speed gearbox in unit with the four cylinder engine. The multi-plate clutch runs in oil, 19-inch wheels are fitted, weight is about 330 pounds. In 350cc form, 46mm × 52mm bore/stroke power is 46 bhp @ 11,000 rpm.
MV AGUSTA, the Gallarate firm which, up until now, has won more world championships than any other factory, introduced their four-cylinder machine in 1950. Following Gilera's scheme, development, in fact, was carried out by a staff of engineers from Gilera, but featured such novelties as shaft drive, steel in torsion suspension, etc. However, most of these innovations were abandoned and the MV is practically a replica of the Gilera, the only noticeable difference being bore/ stroke dimensions which are 53mm × 56 mm. MV also has a 350 version (47mm × 49mm) which has the same power as the Gilera 350. Needless to say, MV is the factory that has won the 500cc class six years running, while Honda has captured the 350 honors in spite of some good performances given by Mike Hailwood. The truth is that, like the Gilera, the 350 is simply too large and heavy; and, it is not as powerful.
