Updated: Mar 18
THE MOTO GUZZI WIDE ANGLE VEE-TWIN
The first Moto Guzzi Bicilindrica with its ultra-wide angle (129 degrees) vee-twin engine made its racing debut in October 1933 in the Italian GP at Rome’s Autodromo de Littorio located within the city’s Urbe airport. Moto Guzzi team rider Guglielmo Sandri finished second to Fumagalli’s Miller, having remounted after a fall. Two months later, Sandri’s teammate Amilcare Moretti recorded the new bike’s first victory in December’s Naples GP.
For 1934, Irishman Stanley Woods joined the Guzzi works team for selected races. The former Norton works rider had become disillusioned with the performance of the British singles, and began riding the 500cc vee-twins of both Moto Guzzi and the Swedish Husqvarna factory on a race-by-race basis. The Irishman won his first race on the Guzzi Bicilindrica in April 1934 in the Spanish Grand Prix on Barcelona’s Montjuic Park circuit. Despite the win, Woods nicknamed the bike the ‘Monster’ because of its reportedly evil handling and he then switched to Husqvarna for the Senior TT in the Isle of Man. There the Swedish bike ran out of petrol when Woods was on the way to second place.
Meanwhile, Guzzi’s new Italian star Omobono Tenni won the Italian GP in Rome, en route to taking the Italian 500cc National championship with the new vee-twin .Before that, one of the vee-twin Grand Prix racers had been fitted with a speedometer, toolboxes, silencers and a bulb horn for Terzo Bandini to win the 1934 Milano- Napoli marathon at record speed. Bandini duly repeated his success, but in the 1937 sidecar class using a Guzzi Bicilindrica fitted with a Longhi sidecar, while Omobono Tenni underlined the solo version’s long-distance capabilities by winning the 1935 and 1936 editions of the same race. Guglielmo Sandri made it four in a row in 1937, in a 1,283km marathon now extended to Taranto, which saw eleven Moto Guzzi 500s finish in the first 15 places.
During the mid-1930s the Moto Guzzi Bicilindrica swept all before it on the race tracks of Europe, winning the Italian GP (by then restored from Rome to its original home at Monza ) on two more occasions in 1935-36, breaking the 150kph average speed barrier for the first time on the banked circuit. This was on a bike fitted with enormous megaphone exhausts that yielded a top speed of over 180kph,running on 50/50 petrol/benzole and 8.5:1 compression.
But the victory which established the Guzzi Bicilindrica as the leading 500cc bike of its era was Stanley Woods' remarkable win in the 1935 Isle of Man SeniorTT. In rain-lashed conditions, he led Jimmy Guthrie's works Norton home by just four seconds after a thrilling seven lap race and averaged 84.68 mph for the 264-miles. It was the first of several Moto Guzzi victories in the Isle of Man TT as Woods also won the Lightweight TT the same week on a Guzzi 250cc single, to complete what was then a unique double. And after his complaints about its behaviour the previous year, Woods had none in 1935 about the sprung frame for his Senior TT winner that transformed the V-twin’s handling.
The 1936 TT-winning Moto Guzzi vee-twin
In fact, despite its handling advantage Moto Guzzi was itself coming under pressure by the second half of the 1930s as more emphasis was now being placed on power outputs and more and more supercharged machines appeared on the scene. Against the 80bhp-plus blown bikes from BMW and Gilera in he 500cc class, the Moto Guzzi Bicilindrica's hard-earned 47bhp at slightly increased revs of 7,500 rpm by 1935 was insufficient to keep the Italian bike in contention except on twisty circuits. On those tighter tracks, at least, the bike’s lighter weight and easier handling ensured a steady run of successes up to the outbreak of WW2. Having said that, Omobono Tenni and teammate Giordano Aldrighetti did defeat the new supercharged BMW Kompressor twins to finish 1-2 in the 1936 Italian GP on the very fast track at Monza.
By the end of 1937 Moto Guzzi had actually produced a prototype water-cooled supercharged Bicilindrica, though it never debuted in competition. Instead, Carlo Guzzi focused on gradually improving both the Bicilindrica’s cycle parts and engine, aiming to reduce weight and improve the handling. A new frame featured a rear section made from light alloy pressings and this was fitted with uprated versions of the Brampton girder fork. Finally, a beautifully-made big 280mm twin leading-shoe front brake was fitted that was again a decade ahead of its time in concept and execution. This cancelled out much of the weight- saving made elsewhere, but dry weight was now 148kg, and the Bicilindrica at least stopped properly from its terminal speed of just on 190kph.
Despite these significant improvements to the Bicilindrica, its supercharged rivals finally made the breakthrough in 1938, with Dorio Serafini winningthe European title on the Gilera Rondinethe following year. This placed Moto Guzzi under commercial pressure to come up with a machine to beat its biggest Italian rival on racetracks, and its response was to construct its own all-new supercharged three-cylinder machine. But this was stillborn when Italy joined the war in 1940, and the FIM’s postwar ban on forced induction instead gave a new lease of life to the remarkable Bicilindrica.
The 1947 version of the Bicilindrica
When post-war racing resumed, the detuning necessary to run on 72-octane petrol dropped the power output of the Bicilindrica to 42bhp and its top speed to 175kph. Even this, however, was still sufficient to ensure that the 120º V-twin resumed its former supremacy. It took Omobono Tenni to the Italian 500cc championship in 1947, a feat emulated on the same bike by teammates Bruno Bertacchini in ‘48, and EnricoLorenzetti in ‘49. Each of these latter two titles was won with a new machine using a much-revised version of the Bicilindrica that first appearedat the start of the 1948 season. This featured an entirely new frame designed by engineer Antonio Micucci,who had joined Guzzi’s Mandello del Lario factory during the war to work on military machines.
His first racing chassis did however set a trend followed by subsequent Guzzi designers. The frame’s main feature was a 112mm diameter tubular backbone, which also doubled as the oil tank for the five litres of lubricant. A steel cradle now contained the horizontal rear suspension unit incorporating both dampers and springs located beneath the engine, a design feature which caused wonder in the motorcycle world when it appeared 35 years later, on the ELF2 500GP racer!
The 1948 version of the Bicilindrica
A leading-axle telescopic fork replaced the Brampton girders with twin 220mm opposed single leading-shoe drum front brakes now fitted, and a 210mm rear. Only minor improvements were made to the engine for 1948. It still ran on straight exhaust pipes, for example, rather than power enhancing megaphones. Improved aerodynamics, however, resulted in better acceleration and the top speed increased to just over 180kph. This, and the improved handling provided by the new frame, was responsible for Tenni's impressive display in the Isle of Man’s 1948 Senior TT, when he set fastest lap and looked set to win, until delayed by plug trouble.
Apart from more re-styling in 1951, it was the 1949 machine that represented the ultimate version of the Bicilindrica. A comprehensive technical redesign saw the rather massive construction of the steel frame cradle being tidied up. The suspension units were now exposed and the previous steel down-plates were replaced with ones made of light alloy - all of which lowered the bike’s weight to 145kg.The ungainly-looking fuel tank that had been perched on top of the spine frame of the 1948 model was replaced for 1949 by an elegant combined tank and front number plate cowl, with the later-to-be-typical Guzzi steering column sprouting above it, with narrow handlebars and a friction steering damper. This was made possible by the adoption of a leading-link front fork as first employed on Guzzi’s 500cc single a couple of years earlier. The cams for the double front brake were now positioned co-axially with the front wheel spindle, one on each side, while the old-fashioned 21 and 20-inch diameter front and rear wheels were both replaced by 19-inch components. Additionally, there were numerous small engine improvements, including the fitting of graceful megaphone exhausts, and these raised engine speed to 8,000 rpm and power output to 45bhp. This was still on low octane fuel but using 35mm Dell’Orto carburettors. Thanks to the enhanced air penetration of the tidied-up design, top speed was now 200 kph (125mph).
The 1949 version of the Moto Guzzi Bicilindrica V-twin
The various improvements to the 500 Bicilindrica for 1949 were accompanied by the construction of a 350cc version of the wide-angle V-twin, which despite impressive engine dyno results, was only raced once, finishing seventh in the 1949 Swiss GP in Bruno Bertacchini’s hands. Otherwise, the Guzzi works team - now including Britishstar Bob Foster - contested only the 250cc and 500cc classes of the first-ever World Championships in 1949. Bruno Ruffo won the Lightweight title that year for Guzzi, but in the bigger class the Bicilindrica was outsped by the Gilera fours and AJS Porcupine twins on the fast tracks which predominated in the series.
Nevertheless, Foster so nearly won the Senior TT on the 'Red Devil', as the Guzzi Bicilindrica was now dubbed by the British press, leading the race until the sixth of the seven laps, when the outside flywheel nut sheared off -a most unusual occurrence on a Guzzi. As some sort of consolation, he repeated Omobono Tenni's feat of the previous year and set up fastest lap at 89.75 mph. For internal business reasons Guzzi didn’t contest the 1950 Grand Prix season, although a slightly updated bike was loaned to Foster to ride in the Senior TT, where he finished sixth after a minute's stop out on the course for adjustments. The main improvement in 1950 had been the fitting of a more streamlined anatomica fuel tank, with shaped inserts for the rider's knees and arms.
In 1951, the Bicilindrica reached the end of 18 years of continuous development
For 1951, the Bicilindrica's last season as a works machine, the frame was re-designed, by way of being substantially strengthened with an even fatter tubular backbone. Seat and rear mudguard blended into one graceful unit and, in a surprise move, the two hydraulic rear suspension units (still positioned under the engine) were replaced by undamped coil springs. Pivoting links between the main chassis and the swinging arm used old pre-WW2 style adjustable friction dampers at their central pivot point to control the spring damping. This was in an effort to improve suspension response in those early days of telescopic shock absorber units. To reduce the turbulence around the front wheel, the operating arms for the central brake cams were located inside the brake drum. Engine wise, in an attempt to equalise the V-twin’s carburation between front and rear cylinders, the rear Dell’OrtoSS carburettor was mounted on an extended inlet tract, which had its intake almost level with the rear wheel spindle. Valve sizes were now 35mm inlet and 33mm exhaust, and power up to 47bhp at 8,000 rpm. Top speed through the Monza speed trap was 210kph (130mph) – some going for an 18 year-old pre-war design!
But it was the Bicilindrica's dependable attributes of easy handling coupled with a smooth power delivery which gave it one final victory that year, when Fergus Anderson trounced all the other works teams to win the 28-lap 127-mile Swiss GP on a slippery and treacherous wet Bremgarten track, complete with cobblestones, with teammateLorenzetti third. It was the final Grand Prix swansong of a great motorcycle, although private owners were still winning non-Championship races with the vee-twin a full twenty years after its 1933 debut,
Fergus Anderson won the 1951 Swiss Grand Prix - the final victory for the Bicilindrica
For the full story of the Moto Guzzi Bicilindrica vee-twin, check out our individual Motorcycle Files e-book on this long-lived and highly successful racer. It is also one of the subject of Moto Guzzi Classic GP Racers - a paperback print book in our Great Racing Motorcycles series which also features the legendary Guzzi 500cc V8 and other 500cc, 350cc and 250cc champions and challengers from the fabled Italian marque.