Mondial 250 Bialbero Racer

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Sport: Mondial 250 Bialbero Racer

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The small Italian brand FB Mondial made racing history. At the height of its success, with the world title in the 125cc and 250cc class, Mondial withdrew from racing in 1957. One of the 250cc racers is in the Sammy Miller museum and brought back old memories to the author.

Ja, sure – a 250cc Mondial is for sale somewhere in the USA. Once again one of those utopian “Honda six-cylinder 250s for sale in Transylvania” fairy tales that go around from time to time. So I did not respond immediately to this information.

Sport: Mondial 250 Bialbero Racer

Fairytale figure

Lucky deal: battered, but complete

Well, the answer to that question will forever remain hidden in the fog of time, but I bought the Mondial and brought my booty to England in 1980 in a battered but complete condition. My buddies Ron Lewis and Dick Linton rebuilt the engine from scratch after getting Hoeckle in Germany to make new crankpins and connecting rods with the original needle bearings. I drove the Mondial at the TT parade on the Isle of Man in 1983, and this gave me the extensive driving impressions I needed with what was once the ultimate racing single, in addition to the experiences of the few laps that I made exactly 30 years later on Sammy Miller’s fully faired bike was allowed to shoot on his airfield test track around his museum. As third place in the 1957 World Championships, Sammy Miller had a significant place in the glorious racing history of the 250cc Mondial. The small Italian brand, which was able to win world titles in two different classes in one season, has certainly made history. Sammy had been looking for one of the only six copies built for his museum for a long time before he was finally able to get hold of one in Italy in 1993.

So what is behind this brand, which has made it to the top of the world of racing faster than any other, and then retires from racing after barely a decade at the height of its success? FB Mondial was the invention of the Boselli family, whose four brothers (hence the abbreviation FB for Fratelli Boselli = Boselli brothers) founded a motorcycle company in Bologna in 1936. The Bosellis were a wealthy family who owned a lot of land and whose unusual entry into the motorcycle industry can be traced back to the racing successes of their eldest brother Giuseppe between 1927 and 1935. The Bosellis initially concentrated exclusively on the construction of three-wheeled delivery vehicles, powered by a long-stroke 600 ohv single. The FB Motocarro developed into one of the most respected vehicles in its class, but the events of the war and the occupation by the German Wehrmacht ultimately led to the end of the factory – it was destroyed in 1944. Giuseppe Boselli succeeded his father and rebuilt the company in a new, supposedly better location in Milan.

The post-war era created immense demand for vehicles and modes of transport, and new moped and motorcycle manufacturers sprang up like mushrooms. Boselli decided to give the company a special image and used the Italians’ passion for racing. So two years before the first series production machine, Boselli racing bikes were already rolling on the Grand Prix tracks. Mondial was chosen as the new name, preceded by the abbreviation FB, but in everyday parlance the abbreviation quickly fell under the table. The 125cc class was chosen to pave the way for the planned series machines, and although the two-strokes from MV Agusta and Morini dominated the action at the time, the newly recruited designer Alfonso Drusiani chose a stripped-down version of the classic ohc four -stroke single -Formats that would later become so typical of Italian racing engines. Nello Pagani won in the second race ever completed, and the unusual little Mondial would prove to be unbeatable in the following years: from 1949 to 1951 she won all eleven GP races, Pagani became world champion in 1949, team-mate Bruno Ruffo won the title in 1950 and was 1951 Carlo Ubbiali’s turn.

A winning single instead of a massive twin

Nakamura

"A fall in the last corner – I’ve never been this close to a GP victory".

MV Agusta and above all the NSU team triumphed over the next few years, but Boselli had long since had the 250cc class in his sights. This seemed to be reserved for the down-to-earth 350s, but Drusiani took the other path, assuming that a drilled 125cc or 175cc bike would more than make up for its performance deficit with its lower weight and more agile handling. Drusiani pushed the 125 cc to its maximum of 216 cm³, which helped the fully faired bike to a top speed of 190 km / h, but the title this season went to an NSU Sportmax. Realizing that the 216 single was not victorious, Drusiani began working on a real 250 twin by planting two 125 cylinders on a common crankshaft. When the complete bike rolled out at the start of the 1956 season, its massive appearance was only topped by its enormous weight – it weighed around 140 kilograms. The cylinder dimensions were the usual 53 x 56 millimeters at the time. And although it delivered the same performance as its eternal competitor NSU Rennmax with a specified 35 HP at 10,000 rpm, the Mondial Bicylindica did not play in the same league. The weight disadvantage was reflected in acceleration and braking, which led to the first use of a disc brake we have racing motorcycle. But Drusiani quickly realized that this white elephant he had created would never be competitive, and the twin was quickly scrapped. The best solution would be a real 250cc single, and so in the winter of 1956/1957 the Mondial engineer designed a bike that many, not least the great Mike Hailwood, consider to be one of the best single-cylinder racing bikes of all time . The new Mondial wet sump single with an upright cylinder and two overhead camshafts came with a significantly oversquare design, had the same stroke (56.4 mm) as the 125, but a significantly larger bore of 75 millimeters and allowed a maximum speed of 11,400 / min , with a maximum output of 29 hp at 10,800 rpm. With a weight of 110 kilograms including full fairing, the new Mondial was a much more serious competitor than the massive twin, especially in view of the new tubular steel frame that it had in common with the 125cc. The 250cc Mondial in Monza was measured at an incredible 219 km / h, faster than most of the 500cc singles. The large 220-millimeter double-cam drum brake at the front was specially made for the 250, the large cooling openings should take into account the typical problems with the Streamline cladding.

A young Northern Irishman named Sammy Miller joined the strong driver team consisting of Provini and Sandford at the 1957 TT. It could have been a truly magical story, because Miller was leading to the last corner in the 250cc TT race, Governors Bridge, when he became cocky with the checkered flag in view. “I gave a lot of gas out of the last corner, the machine crossed and I fell. I picked up the bike, but the engine wouldn’t start, so I pushed the 250 up the mountain for the last half mile and finished fifth. I’ve never been this close to a Grand Prix win again, ”says Sammy wistfully. Nevertheless, there were successes. Miller finished third at the Dutch TT in Assen and a week later even second at the GP in Spa. Team-mate Provini had shone there with impressive speed, although basically all Mondials were technically identical. Much later, Provini revealed his little secret to Miller. “I had my own special camshafts that were always installed no matter which of the bikes I was supposed to ride in the race. This and a few other modifications gave me that extra bit of power. Look, I was the only Italian on an Italian team, with Italian mechanics who were all my friends – so what do you expect? ”Well, Provini was world champion in the 125cc class, Sandford took the 250cc title. “It was a dream come true,” Boselli told his former driver Miller many years later. “A perfect moment that could never be repeated. We could only have lost if we had continued – so I decided to quit. ”On September 15, 1957, the news shook the racing scene that the double world champion FB Mondial is withdrawing from racing.

And now I found myself in 1983 on the 250cc, freshly renovated by my buddies, at the start of the TT, almost choking on the exhaust plumes pregnant by Castrol R and almost numb from the thundering roar of the numerous Norton Manx around me. The long wait at the start with the engine getting hotter made the Mondial cough a few times afterwards downhill at Bray Hill, but once in the last of the five gears, the single purred happily below me. The elaborate camshaft drive made a lot of mechanical noise, and the exposed valve springs were busily messing up my left boot and long exhaust with oil. Given the age and sensitivity of the engine, and in the absence of spare parts, I kept the revs below 9000 rpm and, despite the tame camshafts installed, I had enough rev range not to starve to death in tight turns. A roar at 4600 / min announced the performance, which started quite clearly at 5200 / min and opened up a 4000 revolutions wide usable band. Despite the tiny wheelbase of 1270 millimeters, the seating position turned out to be ideal for me – thanks to the seat mounted far back over the rear axle. Basically, the Mondial turned out to be quite large for a 250cc, but it still had fantastic handling. It was a pleasure to chase the little 250 through the corners and turns of the Glen Helen section while the roar of the exhaust echoed off the rock walls. No question about it, in terms of handling and braking, the Mondial had passed all tests.

Basically, the 250cc Mondial is a carefully constructed and neatly manufactured, quite conventional motorcycle that owed its success in 1957 mainly to its extremely efficient, aerodynamic fairing, which, according to Sammy Miller, was also not very sensitive to crosswinds. The latter can only be congratulated on his excellently restored specimen. But what happened to my Mondial, you might ask? Well, I sold it to buy my first Paton, the 250 twin, with the proceeds. Today the Mondial is owned by a collector in the USA. So if you hear another fairytale story like “Honda six-cylinder 250 for sale in Transylvania”, go there immediately. It could be true after all.

Technical data: Mondial 250 Bialbero Racer

Engine: Air-cooled single-cylinder four-stroke engine, two overhead camshafts driven by gears, two valves, bore x stroke: 75 x 56.4 mm, displacement: 249 cm³, compression: 10.5: 1, carburetor: 32 mm Dellorto SS1, Power: 29 HP at 10800 rpm, five-speed gearbox, chain drive.

Landing gear: Double-loop tubular steel frame, 35 mm telescopic fork from Marzocchi in front, tubular steel two-arm swing arm with two
Girling spring struts at the rear, duplex drum brake at the front, Ø 220 mm, simplex drum brake at the rear, Ø 220 mm, tires front 2.75 x 18, rear 3.00 x 18, dry weight: 110 kg (with full fairing) , top speed: 219 km / h, www.sammymiller.co.uk/museum.

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