TONTI LEGACY
In our ongoing series on pivotal Italian designer Lino Tonti, we look at how the fortunes of former motorcycle giant Bianchi might have been different they had fully developed Tonti’s 500cc racing twin
When Bianchi decided to make a return to road racing, the man they turned to was Lino Tonti. Alan Cathcart looks back on how this great engineer tried to work magic with a miniscule budget
The return of the Bianchi factory team to Grand Prix road racing in 1960 was as unexpected as it was quixotic. It had been almost 40 years since the ‘Mighty Mouse’, Tazio Nuvolari, had put Italy’s oldest motorcycle manufacturer on the road racing map. He won a host of 1920s GPS, riding the magnificent dohc Freccia Celeste (Blue Arrow) 350cc single, painted in the company’s trademark sky blue colours.
Bianchi’s success continued in the ’30s, as the company’s close links with Mussolini’s ruling Fascist party were exploited to allow it to boom commercially, becoming Italy’s largest motorcycle and bicycle manufacturer. Bianchi moved into the 500cc class in 1935 with new superstar Dorino Serafini, albeit racing mainly in Italy due to widespread anti-italian feeling abroad in the wake of the nation’s invasion of Abyssinia (now Ethiopia), and the consequent League of Nations embargo on trading with the country. By now the firm, which had grown out of the bicycle workshop which founder Edoardo Bianchi had established in Milan back in 1885, had become a huge automotive empire, producing cars, trucks and even aircraft as well as world-class bicycles.
Motorcycle racing initially took a back seat, but eventually Bianchi decided to follow Gilera’s lead (to whom Serafini had switched in 1938) and developed a new supercharged 500cc four-cylinder racer. This appeared in public for the first time in 1940, but was never raced, after Italy joined in the war in support of Nazi Germany.
Bianchi’s Viale Abruzzi factory in Milan was destroyed by Allied bombing in 1943, and it took until 1950 for the plant to be rebuilt. But before then Bianchi had managed to restart motorcycle production, and thus rode the wave of demand for economical post-war transportation, which fuelled the racing comeback of rival bike firms like Moto Guzzi and Gilera. Bianchi, however, chose not to race. Edoardo Bianchi had passed away in 1946 at the age of 79, and it had been Il Commendatore who was most passionate about the sport. His son Giuseppe inherited the company and fancied himself as a hard-nosed businessman. He’d travelled widely abroad PRE-WWII, studying industrial management, and realised that bikes sold themselves in such a flourishing market, so why go racing? He instead spent Bianchi’s race budget on buying bicycle success in backing legendary Italian rider Fausto Coppi.
In 1955 the company’s four-wheel division was sold to Fiat and renamed Autobianchi, so Fiat’s Agnelli family had shrewdly removed the only potential threat to the Cinquecento’s market dominance. However, cash from this sale didn’t arrest Bianchi’s commercial decline, so in the late ’50s Giuseppe – by then spending much of his time in Australia, for personal reasons – decided to dust off his dad’s idea of promoting Bianchi motorcycle sales by going Grand Prix racing again.
In September 1958, Lino Tonti was hired by Bianchi as chief engineer. His duties included responsibility not only for expanding its range of motorcycles, scooters and military bikes, and developing competitive 250/400cc off-roaders which duly won the Italian motocross championship, but also creating the Grand Prix road racers with which the historic Milan company intended to make its competition comeback, as a means of promoting the brand.
After failing to convince Bianchi directors to give him a budget big enough to develop a 250 four, Tonti
‘IN 1958, LINO TONTI WAS HIRED BY BIANCHI AS CHIEF ENGINEER’
‘contented’ himself with designing a 250 twin which he fully intended from the beginning should be capable of being stretched to provide a modular contender for the 350 and 500cc classes as well. “This way, on a restricted budget, I could develop a single design capable of competing in all three classes,” he said. But the 128kg 250cc, developing a claimed 34bhp at 11,500rpm, was too heavy against the early ’60s Honda 250 fours weighing 10kg less, and producing up to 20bhp more.
The 1960 five-speed 250cc (55 x 52.5mm) twin – a more modern short-stroke design compared to the 53 x 56.4mm Mondial-paton he’d worked on in 1958 before joining Bianchi – set the format for all Tonti’s future Bianchi GP designs, irrespective of capacity. He first raised capacity to 348cc at the end of 1960 via a 10mm overbore, with 32mm Dell’orto SS1 carbs replacing the 250’s 27mm items, and also fitted a six-speed gearbox. This increased power to a claimed 50bhp at 10,600rpm, but the capacity was further increased to 386cc in 1961 to create the company’s first Italian title-winning 500cc contender ridden by Tino Brambilla, still retaining the same 52.5mm stroke, but with a 68.4mm bore. Thereafter, capacity crept to 405cc, then to 425cc and finally to 454cc (70 x 59mm) for Remo Venturi to win the 1964 Italian 500cc championship, with a claimed 67bhp at 10,100rpm at his disposal.
However, considering that Gilera’s four-cylinder gave a genuine 67bhp, this was surely an optimistic PR figure, and according to dyno readings which Lino Tonti kept in his possession, the true figure was 62bhp, at the same revs!
Finally, during the course of 1964, Tonti obtained the
resources to do the job properly, creating a similar-format full 498cc engine measuring 73 x 59.5mm, with 20mm wider and more robust crankcases. The 500 twin was claimed to deliver 70bhp at the gearbox at 10,200rpm, as well as substantial extra torque aimed at redressing the acceleration handicap it suffered from against MV’S four. But with money running short, development took longer than expected, and it was never raced.
Instead, it was with the 454cc stretch-twin that Venturi defeated the MV Agustas to win a well-deserved Italian championship, after winning the opening two rounds at Modena and Riccione, and finishing second in three other rounds. However, it was in the Dutch GP at Assen that year that Bianchi arguably had their finest hour, Venturi finishing second behind Mike Hailwood’s MV in the 500 race, and third behind Hailwood and winner Jim Redman’s Honda in the 350.
In what was to be the works Bianchi team’s final GP race at Monza, Venturi teamed up with Alberto Pagani for the 500cc race, in which he was running third before his rear suspension collapsed, but soldiered on to finish tenth while Pagani retired with a vibrating engine. But in the 350cc race Venturi rode like a man inspired, leading Redman’s Honda four for several laps before being forced to retire with ignition trouble, after setting a new outright 350cc lap record at 117mph, which lasted for many years and well into the two-stroke era.
The dohc Bianchi engines with separate vertical cylinders featured a robust fourbearing built-up roller-bearing crankshaft carrying conrods machined from solid steel billet, with H-section reinforcement. The 360º crank (the same two-up piston format as on British twins) differed from Paton parallel twins which employed a one-up/one-down 180º layout, aimed at reducing vibration, and theoretically allowing higher revs.
The Bianchi crankshaft featured fullcircle flywheels, with a secondary layshaft positioned behind it and driven at half engine speed off the centre of the crank which, in turn, drove the twin-spark ignition and oil pump. This auxiliary shaft also drove the inlet camshafts via a train of gears enclosed in a casing between the cylinders, then the exhaust cams via two more gears running across the top of the separate cylinder heads.
Although Tonti actually designed a desmodromic cylinder head for Bianchi’s 350 (Mondial had already tested such an engine, but abandoned it when its progenitor Fabio Taglioni left for Ducati in 1954), this was never used owing to a lack of resources to develop it. So the two-valves-percylinder (a 43.5mm inlet on the 454cc version, and 37mm exhaust, with the 350’s measuring 39/35mm respectively) each featured a pair of hairpin springs. Tonti said he chose these over coil springs for their lighter weight, greater reliability at higher revs by the standards of the era, and the fact that shorter rockers were needed for their operation. The valves were positioned in the hemispherical combustion chamber at an included angle of 78º (relatively advanced for the time, when Taglioni’s Ducati racers for example had a 90º valve angle) accommodated by deep inserts in the full-skirted Asso forged pistons running in cast iron liners. The compression ratio was a pretty low 9.8:1 (10:1 on the 350), perhaps reflecting the quality
‘TONTI INTENDED HIS 250 TWIN TO BE STRETCHED TO 350 AND 500 CLASSES’
of fuel available at the time. The shape of the pistons, with high flattened crowns, dictated dual ignition with two 12mm plugs per cylinder and four Bosch coils, powered by a total-loss 12-volt battery.
Carburation was by twin 35mm SS1 Dell’ortos (32mm on the 350), with a single central remote float chamber. On the full 498cc version these were elliptical-choke 38mm items specially made for Bianchi. A four-carb version of the engine was also tried, but never raced. Tonti was developing a four-valve cylinder head design when the company went under.
The vertically-split aluminium crankcases (magnesium was used only for the outer covers) on what was effectively a dry-sump engine, with the typically Italian long, finned, magnesium sump beneath them well separated from the crankshaft chamber, had one very advanced feature. Bianchi was the first to use a cassette gearbox, which could be extracted complete from the left side without removing the engine from the frame, in order to change internal ratios on the six-speed transmission. A seven-speeder was experimented with, but never raced.
Bianchi’s original Norton Featherbed-style double-cradle chassis, made from relatively small-diameter chrome-moly steel tubing, was relatively conventional on the earlier versions of the bikes, save for twin bracing tubes running from top and bottom of the steering head to a common mounting point low down in front of the crankcase. But for the 1964 season this was replaced by something much more unusual, which allowed Venturi to beat the MV fours to win the Italian title on his 454cc Bianchi twin. Christened the ‘Bikini Frame’ by Italian fans – for whom the recent arrival of the two-piece swimsuit on the country’s beaches was hard to forget! – this bolted-up twopiece open-cradle frame which used the engine as a fully-stressed chassis component was literally hinged in the middle of the upper frame tubes, making removing the engine very easy. The twin bifurcated downtubes were more substantial, delivering a very stiff front-end package, but this design also featured a much longer swingarm, which helped improve traction – and thus acceleration – as well as delivering a more forward weight bias. Together with a reduced frontal area, thanks to the lower overall build and more aerodynamic riding position, these were all factors which later became commonplace in GP chassis design, which Tonti was a leader in recognising.
Arces forks, specially developed for Bianchi, were originally fitted to the different-capacity Bicilindrica racers, before being replaced by the ubiquitous 35mm Cerianis, set at a 28º rake. Brakes on the 350/500 were Bianchi’s own design, made for them by Grimeca. Both were 230mm magnesium drums with their distinctive ribbing for extra strength, but with the front a doubled-up four-leading-shoe version of the rear two-leading-shoe drum. From the very beginning the short-wheelbase (1330mm) bike was designed to run
‘TONTI WAS DEVELOPING A FOUR-VALVE HEAD WHEN BIANCHI WENT UNDER’
on the then-new 18in wheels, in turn contributing to a low, compact package which Tonti intended should have quick steering and a low frontal area, to make the most of the available horsepower when competing against the MV and Honda fours.
At 132kg dry in 500cc form (128kg for the 250/350), the Bianchi twin was now lighter than even the Manx Norton and Matchless G50 singles it was most frequently racing against, while also weighing considerably less than the Honda and MV Agusta (and later Benelli) fours.
The bold battle against the insurmountable financial odds ended in the and inevitable outcome – Bianchi filed for bankruptcy. Although an abortive attempt was made to nationalise the company under the IRI umbrella – as would later happen with Ducati and MV Agusta – the state-owned option never took off.
Instead, the Bianchi name was sold to Piaggio, which shut down the motorcycle division but continues to this day to manufacture and race Bianchi bicycles very successfully. Ironically, in 1969 Piaggio also acquired Bianchi’s neighbouring rivals, Gilera.
Back in 1964, the liquidator was obliged to sell off Bianchi’s remaining assets – and that included the GP bikes. Venturi, who was owed his entire 1964 racing salary and expenses, was unable to persuade the suits to give him any of the bikes in lieu of what was due to him. To add insult to injury, the fact that he’d been bankrolling the team’s entire race season out of his own pocket meant he didn’t have the funds to buy any of the bikes for himself!
However, Grassetti reappeared on the scene and bought a 350 Bianchi with his personal sponsor’s money, racing it successfully in Italy for two more seasons (including a second and a fourth in the 1965/66 Italian GPS respectively), while a 454cc bike went to the glove-maker gentleman Grand Prix rider Gianni Perrone.
Tonti was allowed by the liquidator to take the other unraced, full 500cc prototype engine and sufficient parts to build a complete bike. It was eventually sold to a collector near Venice who assembled the bike and, in 2003, brought it to an historic event at Misano for Venturi to ride.
“I loved racing for Bianchi,” said Venturi. “Every single thing I ever asked for was immediately done – quite the opposite of MV Agusta, where you were supposed to ride the bike exactly as they gave it to you and consider yourself fortunate to be allowed to do so! Bianchi was completely different, and it’s just a shame that they were always so short of money, because Ing Tonti created a very finehandling motorcycle which only lacked acceleration against the MV fours. But if we could only have had the full 500cc version, I honestly believe it would have allowed us to be contenders for the 500cc World Championship.”
If only...