From our Old Bike Archives – Issue 65 – first published in 2017.
Story and photos: Jim Scaysbrook
Gilera is best remembered for its fire-engine red four-cylinder racers that dominated the 500cc Grand Prix class for years. But it was a modest OHV single that saved the company’s bacon.
The humble 150cc Gilera, handsome though it undoubtedly is, hardly represents ground breaking design. Yet this machine went on to become the largest volume seller in the famous Arcore company’s history, with sales of 96,000 in just over a decade of production, from 1949 to 1960.
The story really begins with the birth of Piero Remor in Liguria in 1989 – a man who would entrench himself in the annals of motorcycling history with his brilliant racing designs. In 1923, Remor, in conjunction with Carlo Gianini, designed a four-cylinder engine for motorcycle racing, but having no funds to develop it, the pair fell in with the entrepreneurial Count Luigi Bonmartini, who owned a number of automotive and aviation companies. It took a further six years to build the complete machine, and the highly successful Piero Taruffi was hired to test it. Inevitably, Remor quarrelled with the Count and quit in 1930, while Taruffi pressed on with development of the racer, which soon boasted full water cooling. When Bonmartini sold his business to Milan-based aircraft manufacturer Caproni, the racer project, which had acquired the name Rondine (“Swallow”), was abandoned, but Taruffi managed to convince Giuseppe Gilera to take it over. This series of events led to Remor joining Gilera in 1939 with a view to developing the engine he had conceived 16 years before, into a supercharged 500, as permitted by the Grand Prix regulations of the time.
But the Second World War altered the course of that plan, and when racing resumed post-war, the FIM banned supercharging. As we now know, Remor went on to turn the Rondine into a world-beater, especially after Gilera hired Umberto Masetti, who delivered them the 1950 and 1952 500cc World Championships. English superstar Geoff Duke added three more, from 1953-1955 and Libero Liberati gave the factory a sixth and final crown in 1957.
But while Grand Prix racing produced the headlines in newspapers and magazines, Gilera needed to make a living from its customer-focussed products. Immediately post-war, and cash-strapped like the rest of Italy, Gilera turned to revamped pre-war versions of the Nettuno and Saturno – large, heavy and out-dated machines that were too expensive for the public that was clamouring for reliable everyday transport. Gilera instructed Remor to design a new range of small single-cylinder models, beginning with a 125, but from the outset the two men failed to see eye-to-eye on the specification. While both agreed it should be a four-stroke, primarily to differentiate the new model from its mainly two-stroke opposition, Gilera wanted a side valve design while Remor demanded overhead valves. In the end, Gilera, who was paying the bills, won, and the result was the Gilera 125 that was presented at the prestigious Milan Salon in 1948. It was a good looker, but in terms of performance, the new machine was sadly lacking, and this was communicated in no uncertain terms by journalist road testers and Gilera dealers. The new 125 produced just 3.5 hp, and could barely struggle to 70 km/h. Much of this lack of poke was due to the dreadful fuel available at the time, necessitating a compression ratio of just 5.5:1.
An urgent re-design was required, and this time Remor got his way with an overhead valve arrangement – almost. Giuseppe Gilera dictated that many components from the limp side-vale needed to be used, including the basic cylinder block, which severely compromised Remor’s plans. Once more, Remor packed his bags, heading this time for rival MV Agusta, along with Gilera designer Artuo Magni. But before he left, he did complete the new 125, which was revealed to Gilera dealers and members of the press in March 1949. This time, the response was much more enthusiastic, and this optimism translated to the showroom when the 125 went on sale at a price similar to the rival two strokes. Power was up almost 30% to 4.7 hp, and top speed up to 80 km/h. Vitally, fuel consumption (an amazing 2.2 litres/100km) was also better than the two strokes, and Gilera was faced with the embarrassing situation where it could not meet demand, struggling to produce more than 500 units per month.
Gradually, as materials became more readily available and production methods improved, around 1,000 per month was achieved, and the 125 also went through a series of detail improvements in both the engine and chassis, which now sported swinging arm rear suspension controlled by friction dampers. Soon, the range expanded to two models, the Sport and the Tourismo, but an act of legislation was to force another rethink. In the frantic rebuilding program that followed the end of the war, great emphasis was placed on the construction of autostrada, or motorways, and these roads were governed by different rules – one specifically banning motorcycles of less than 150cc.
Gilera’s response was to produce a new model, the 150, which was achieved by enlarging the 125’s bore from 54 mm to 60mm, giving an actual capacity of 152.68cc. Again, the new machine was offered in both Sport and Tourismo versions. The 125 continued in production but became mainly an export model. Initially, the new 150 models were distinguished by the front suspension, with the Tourismo retaining the 125’s girder forks, while the Sport received a new, lightweight telescopic fork. Within 18 months, both models gained the telescopic front end, and the rear friction dampers were replaced with conventional spring/hydraulic units. As on the 125, the cylinder head incorporated parallel inlet and exhaust valves – a feature that was to become a Gilera signature – with an alloy, finned rocker box cover. The flat-topped piston featured four rings, and the cylinder barrel was inclined at ten degrees. The spark plug was located at the right side of the cylinder head, fired by a magneto, with a 6-volt dynamo for lighting. Carburation was by an 18mm Dell’Orto. An impressive looking tubular steel frame had widely-splayed front down tubes which did not extended beneath the engine. Aluminium 19-inch rims, fitted with 2.50 x 19” tyres, were standard fitment front and rear, with equally impressive looking finned 150mm brake drums at each end. The first 150 models, which came on stream in late 1952, also retained the three-speed gearbox, with helical gear primary drive and the wet, 6-plate clutch from the 125. By 1953, an extra ratio had been added to the transmission.
Clearly, the 150 was what the buying public wanted, and Gilera responded with the introduction of the Gran Turismo in 1955, followed by the Super Sport and Super Red in 1957. In addition to the almost 100,000 150s built at Arcore, a considerable number was produced at Gilera’s factory in Argentina to supply the South American market.
The now venerable single cylinder design was further modified in 1956 to appear as a 175, but marketed under the curious title of the 150V. The consequence of this marketing goof was quickly realised and the 175 thereafter was sold as the G 175. The largest of the singles was never as successful as the 150, selling only 10,500 units from 1956 to 1960, when production of both ceased.
Despite the success of the single cylinder models, Gilera decided in 1953 to produce, at great expense, what was effectively a doubled-up 150, the B300 twin, which had an actually capacity of 305.3cc. This retained the 60 x 54 dimensions of the 150 single and was shown to great acclaim at the Milan Show of November 1953. Initially the B300 produced only 12.8hp at 5,800 rpm, but subsequent versions increased to 15 hp at 6,800 rpm. The B300 had a long life, remaining in production until 1969.
But to the 150 goes the honour of Gilera’s most successful motorcycle, in terms of sales. Although the 150 and 175 were quietly dropped from the range in 1960, the 150 reappeared 12 years later as the 5V Arcore, but in the face of the new models from Japan, remained in production for just three years.
Specifications: 1952 Gilera 150 Tourismo.
Engine: 2 valve, 60 x 54
Power: 7.3 hp at 6700 rpm
Carb: Dell O’rto MA 18B
Fuel capacity: 13l
Wheelbase: 1300mm
Transmission: 4-speed, gear primary; 6 plate oil bath clutch
Frame: Double cradle steel tube,
Suspension: Front: Girder in pressed steel and elliptical spring
Rear: Swinging arm with two friction dampers.
Brakes: 150mm front and rear
Tyres: 2.50 x 19 front and rear.
Weight: 90kg
Speed: 100km/h
Vale: Gianni Minisini
The 150 Tourismo featured here belonged to Adelaide enthusiast Gianni Minisini, and was typically restored in his meticulous fashion. We have featured several of Gianni’s bikes in OBA, all of them originating in his home town of Udine, in north eastern Italy. Gianni collapsed and died at his Adelaide home, apparently from a brain haemorrhage in 2018. We extend our solemn condolences to his family. A fitting tribute to this quiet achiever was published in OBA 75.
