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Linto-500

LINTO 500 – Double Trouble

April 4, 2016

In World Championship Grand Prix racing, the early ‘sixties was a period of increasing drudgery in the so-called premier class, the 500cc senior. MV Agusta, the only works team left after the wholesale withdrawal by the Italian factories at the end of the 1957 season, pretty much won as it liked each year with riders John Surtees, Gary Hocking, Mike Hailwood and Giacomo Agostini racking up titles with metronomic regularity. The ageing British singles from Norton and Matchless rarely got a look in unless MV stayed away, as they occasionally did once the Senior championship had been again secured.

Honda briefly stepped in with their underdeveloped 500cc four cylinder RC181, but after two attempts in 1966-67, even the genius of Mike Hailwood (plus recurring gearbox problems) failed to net the Japanese factory the coveted title.

Linto 500

Meanwhile the privateers comprising the overwhelming bulk of the grid not just in grands prix but in the Senior class around the globe, struggled on with what they had, or could make. There were moments of inspiration, such as Percy Tait’s second place to Agostini at the Belgian Grand Prix of 1969 aboard a factory-developed 500cc Triumph twin. The Czech Jawa/CZ squad often got amongst the top six with their intricate but underfinanced twins and fours, and even the Russian Vostok four grabbed the odd point, but this did nothing to alleviate the privateers’ plight.

A ray of hope appeared with the 500cc twins developed by Giuseppe Pattoni, formerly the chief mechanic of the FB Mondial squad, initially in conjunction with Lino Tonti, who had designed the twin-cylinder Bianchis. Called Patons, the 500s evolved through a series of 125cc and 250cc twins, and were partially funded by Scottish car and motorcycle dealer Bill Hannah. British rider Fred Stevens finished fourth in the 1966 season-ending Grand Prix at Monza, and the following year Stevens and team mate Angelo Bergamonti performed well at several rounds. Probably Paton’s best year was 1969, when Billie Nelson finished fourth in the 500cc championship, but when Hannah’s money dried up in 1970, the team’s fortunes faded as well.

Tonti had ideas of his own, and began developing an engine using a pair of 250cc Aermacchi Ala d’Oro barrels and heads mounted on a crankcase of his own design. It was christened the Linto and this time, it seemed a sufficient quantity would be produced to allow struggling privateers to replace their venerable British tackle. The venture was financed by former racer and then-president of the Varese Moto Club, Umberto Premoli, with Alcide Boitti assisting with the engineering work.

The new twin made its competition debut at the traditional early-season meeting at Rimini on the Italian Adriatic coast in April 1968. The two ‘works’ entries, ridden by Alberto Pagani (son of 1949 125cc World Champion Nello Pagani) and Guiseppe Mandolini, showed plenty of speed, but both were sidelined with electrical woes – the beginnings of a familiar pattern. In the Linto’s first GP in Holland, Pagani retired with a broken exhaust pipe, but scored an excellent second place behind Agostini at the East German round.

The Linto engine’s vital statistics were a 72mm x 61mm bore and stroke, and as well as the major top end castings, utilized standard Aermacchi valves, valve springs, cam profiles, pistons and conrods. Like the Aermacchi, the engine’s cylinders were almost parallel to the ground, but in the Linto’s case, the vertically-split gearbox bolted to the back of the crankcase rather than being cast in-unit with the engine. Down below sat a four bearing pressed-up crankshaft (actually two separate units keyed together with two outer ball races and two inner roller bearings) with 360º crank settings, although the prototype engine had been built with a 180º crank. This was abandoned after Tonti found it impossible to tame the vibrations caused by this layout, but the 360º option still vibrated considerably. Primary drive was via a jackshaft on the right side, running in roller bearings to a sixspeed gearbox with a dry clutch. Tonti had used this system on the Bianchi twin, and Honda adopted it for their 250/350 six, but it was to prove the Achilles Heel of the Linto. Power was quoted as 61bhp at 9,800 rpm, with a compression ratio of 10.0:1. Initially the Ceriani factory, from nearby Cardano supplied the brakes and front and rear suspension. At 135kg, the Linto weighed the same as a G50 Matchless, with 20% more power. However in contrast to the simplicity of the British singles, the Linto was a fiendish device to set up. Valve timing in particular called for a surgeon-like touch, requiring the crankcases to be split to adjust the timing.

Development of the works machines continued throughout the 1968 season, where Pagani finished an encouraging equal fourth in the 500cc championship standings. Jack Findlay was invited to test Pagani’s machine at Monza late in the year, but suffered a massive crash at the flat-in-top-gear Corva Ascari when the Linto seized. The bike was completely wrecked, but once again, “Aussie Jack” escaped with minor injuries. On examination, it was found that the primary gear drive had broken up, locking the engine (and the rear wheel) instantly.

For 1969, plans were announced for a production run of 12 machines, with two bikes (finished in blue instead of the standard red) to form the works team of Pagani and Findlay. Power output was now up to 64bhp at 10,000 rpm, with a pair of 35mm Dell’Orto SS remote bowl carburettors supplying the mixture. Asking price for the ‘customer’ models was £1,300 apiece (when a good second hand 500cc Manx Norton fetched around £450 and a new Seeley G50 £750), and there were plenty of takers, including Australian John Dodds, consistent Swiss-Hungarian Gyula Marsovsky, Kiwi Keith Turner, and British privateers Maurice Hawthorne, Steve Ellis and Lewis Young (whose mechanic/gopher was a teenage Barry Sheene). However what looked like being a great season for the new Italian marque turned into a disaster – although Pagani’s works bike did score Linto’s first and only Grand Prix win at the Nations Grand Prix at Monza (with Dodds’ private model third in a rare finish and claiming the fastest lap of the race) after Count Agusta ordered his team to boycott the event. For Findlay, who had finished a clear second in the 1968 500cc title on his McIntyre Matchless, the Linto was almost a career-breaker. After finishing third in the second round in West Germany, the Linto’s chronic unreliability (including a massive blow up at the North West 200 when the primary gears stripped) caused the laconic Australian to park the bike and return to a privately run Norton and later an over-bored 382cc Aermacchi single. So stretched were the venture’s finances that priority was given to supplying paying customers rather than supporting the works machines, and Findlay was in no position to sit out races waiting for Linto to repair his machine, or its spare engine.

Ironically, Linto’s best results during 1969 were achieved by Marsovsky and the British rider Steve Ellis on customer models. Marsovsky finished runnerup to Agostini in the final standings, despite missing the last round in Yugoslavia after he suffered serious injuries in the notorious Freiburg Hill Climb in Germany. For the other Linto runners, the season was a litany of mechanical failures; broken valve gear, pistons, primary drives and frames that cracked under the effects of vibration. By mid way through the season, several of the twins were parked in the GP paddocks with “For Sale” signs. Pagani (on the works model), Dodds and Ellis soldiered on into 1970 on Lintos, although Ellis went back to a G50 Matchless before the season was out. By now the two-stroke “menace” had infiltrated even the premier class; the triple cylinder Kawasaki H1R providing speed and reliability for a large number of privateers, including Kiwi Ginger Molloy who finished second to Agostini in the 1970 table.

For the 1970 season, Premoni announced that a further 15 machines would be built for sale, but very few were produced. Perhaps the last one built went to novice French rider Didier Dumesnil in April 1970. Ironically the remaining bikes were now reasonably reliable thanks to the primary drive redesign and the use of electronic ignition, but by now the Linto was being outpaced by the Suzuki twins and Kawasaki triples.

A Linto Down Under

The Linto featured here (engine number 0009) is the motorcycle originally raced by Keith Turner, who in the 1971 season finished runner up in the 500cc championship on a TR500 Suzuki behind Agostini. Turner purchased the bike midway through the 1969 season and finished in fifth place in the final GP at Opatija, Yugoslavia. In 1970, he won the 500cc race at the traditional “season opener” at Le Mans, with Dodds second on his Linto – a rare 1-2. The Linto, apparently by then in a very poor state, was sold to Swedish rider Bo Strandell for the 1971 season and after a complete rebuild was used mainly in Scandinavia, before Australian journeyman racer Dave Stanley acquired it in February 1972. As someone who raced for a living, Stanley was careful with the preparation of the Linto and in the way he rode it, and surprisingly says it was less fragile than most people thought. “The engine is quite willing to spin to 11,500 rpm or even 12,000 and still deliver power. I think the rockers (breakages) were just a bad batch, and the pushrod trouble is understandable. The more you turn the throttle the higher they rev. They just keep on going, and giving more power, until something snaps. 11-12,000 rpm from a pushrod twin is pretty unreal and something has to give. Stanley raced the Linto throughout Europe in 1972 before it seized at what was to be its final outing in Europe. Stanley rebuilt the engine with a new liner, piston, rod and big end, main bearings and gearbox bearings before shipping it back to Australia, where it sat at his business, Dave Stanley Racing Services at Moorabbin, for several months. Eventually, Stanley decided to sell it, although reluctantly. “I’d love to keep the bike because a real Grand Prix racer is what every rider dreams of owning,“ he told AMCN, “but I haven’t got the room here, the money would come in handy and I’d like to buy a water-cooled 350.” When Dave did put it up for sale, he found a ready buyer in Adelaide sidecar racer Graham Lock.

LINTO 500

In a letter to Graham Lock in 1974, Jack Findlay said, “The idea was to provide a 500 production racer for the private owner. Premoli provided the finance to construct 12 or 13 machines (10 were for sale and two were retained as “official” machines). At that time Premoli was a Citroen concessionaire and the motorcycles were constructed in part of his garage premises not far from the Aermacchi factory. This horizontal engine suffered many failures through vibration and although some experiments were tried with the balance factor not enough work was done along these lines because at the beginning of the 1969 season Lino Tonti took up his position with Moto Guzzi and no longer had the time to devote to the development of the Linto. Along with Alberto Pagani, I rode one of the official machines in 1969. These two machines began the season with magnesium crankcases but the vibration was so great it caused the rider’s hands to swell and become numb. When we reverted to aluminium cases as were fitted to the private machines, we found that after several hundred kilometres these would crack horizontally.

During the 1969 season I only finished two races with my machine and one of these, at Rimini, Italy, was lucky because when I crossed the line it was virtually only my arms that were keeping the front end attached to the rest of the bike, as the frame had broken under the tank. It was all a frustrating business as the machine was very fast; in every Grand Prix of 1969 except for the Spanish, I held second position but I was only ever able to finish one – the German – when I was third with a broken valve spring.

Premoli had so many complaints from buyers of his machines that he completely abandoned the project. Remember that he was only assembling parts that were manufactured in various factories around Milano or Varese and any modifications took a long time to organise. To keep the machines running during the 1969 season we often (too often in fact) fitted parts which we knew from past experience would not last. At 10,000 rpm this engine really had good power and these revs were not excessively high as the factory 250 Aermacchi would run up to 11,000, but at 10,000 all the parts of the valve gear in the Linto were prone to failure. Valve spring breakage was the most common trouble, virtually every time I ran my engine, but also rocker arms would break or the pushrods got all twisted up. It seemed that something in the valve gear just had to go.”

According to various reports of the day, Premoli became frustrated with the breakages in the primary transmission and after splitting with Tonti, commissioned the Australian Shaftlietner concern to redesign the primary drive and transmission. This apparently worked and by late in 1970 a degree of reliability had been obtained. By now, Tonti was on Moto Guzzi’s payroll and only 12 Lintos had been constructed. Although he had spent an enormous amount of money on the basically unsuccessful Linto project, the final straw for Permoni came when the loyal Pagani was approached by Count Agusta. MV’s second string rider Angelo Bergamonti had been killed in a race crash and Agusta offered the ride to Pagani, and he accepted. For Premoli, enough was enough.

Graham Lock kept his Linto for 20 years – from 1974 to 1994 – but he just couldn’t refuse an offer of $50,000 from the newly-established Barber Motorcycle Museum in Birmingham, Alabama. And so the famous (or infamous) Italian racer departed this country for a new life on permanent exhibition in America’s Deep South, where it still resides.

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