Where legends live on..

Husqvarna 500 Sweden’s Top Twin Tested

The imminent arrival of the twin-cylinder Husqvarna 900 Nuda street fighter seemingly marks a major change of direction for the Swedish dirt bike brand, which moved to Italy in the late 1980s to join the Castiglioni brothers’ Cagiva empire.

Husqvarna continued to flourish, winning no less than 21 Enduro, four Motocross and five Supermoto world titles under Castiglioni ownership, which generated demand worldwide for the single-cylinder off-road products. These were powered, in the main, by Husqvarna’s two-stroke engines, then later four-strokes after the brand’s move to BMW ownership.

The new Nuda twin appears to mark a dramatic watershed for the Swedish kings of the dirt. But that’s actually not the case, as a look in the history books will confirm. For, way back in the 1930s, Husqvarna actually competed very successfully at the highest level in Grand Prix road racing with 500 and 350cc bikes powered by its own leading edge 50º V-twin four-stroke engine, produced by its legendary designer Folke Mannerstedt.

Sweden is not a country normally associated with the manufacture of exotic road race hardware, but between 1931 and 1935 Husqvarna (aka HVA), then the country’s largest road bike manufacturer, built 19 500cc V-twin works GP racers, and four 350s.

Ridden by men the calibre of British aces Stanley Woods and Ernie Nott, and Swedish stars such as Gunnar Kalén and Ragnar Sundqvist, the Scandinavian bikes not only challenged Britain’s established Norton and Velocette teams they also broke new ground in terms of materials and engine design. While never ultimately as successful as they deserved, the works V-twin Husqvarnas played an important role in the evolution of GP design. They were the first multi cylinder machines to challenge the supremacy of the British singles in 500 and 350cc GP racing, laying the foundations of success enjoyed later in the 1930s by Moto Guzzi and BMW twins, and eventually by Italian four-cylinder bikes, too.

Like BSA and Royal Enfield, Husqvarna was originally a firearms manufacturer, and ironically, it was another such company, Belgium’s FN, which provided the seed for HVA’s road racing effort, thanks to the experience gained by a young Swedish engineer in assisting the Belgian factory with its World Land Speed record attempts on a frozen lake in his home country in 1927/28.

His name was Folke Mannerstedt, and his days at FN convinced him of the importance of several aspects of engine development which we nowadays take for granted in the pursuit of performance, but which 80 years ago were considered avant-garde – stuff like radical valve timing with wild cams giving lots of overlap, improved breathing offered by downdraught induction, and harnessing exhaust resonances to improve cylinder filling, and combustion.

Mannerstedt was also a fanatic for ‘adding lightness’. A pioneer in the extensive use of magnesium and light alloy, he was able to reduce the dry weight of his bikes from 177kg for his prototype 500 V-twin, first raced in 1931, to 127kg for the ultimate version with which British star Stanley Woods won the Swedish GP in 1935. That’s quite some development – imagine what he could have done with carbon fibre and titanium!

DIRT TO TARMAC

Mannerstedt joined HVA as chief engineer early in 1929, inheriting a 734cc OHV 50º V-twin engine, developed mainly for sidecar use, which he simply scaled down to produce a 500cc version for use in that year’s ISDT – then, as now, Husqvarna’s main competition activity was off-road focused. But Mannerstedt was a speed freak, and in spite of general belt-tightening caused by the depression, he persuaded HVA factory bosses to pay some attention to road racing with a 500GP machine based on the ISDT bike, which factory rider Yngve Ericsson took to third place in the 1930 Swedish TT at Saxtorp.

For 1931, Mannerstedt produced his own 500cc road racer which, like its predecessor, was a 50-degree V-twin design, on which future HVA GP machines were all based. Perhaps it was a little over-optimistic to make the bike’s racing debut in the gruelling Isle of Man TT, where both works entries retired, but the V-twin Husqvarna made its mark in 1932, with riders Sundqvist and Kalén defeating the works Norton team to place one-two at the Swedish GP at Saxtorp. Further development lowered weight and increased power during the 1933 season, the ensuing run of race victories and lap records in international races in Sweden and abroad leading HVA management to launch a full-scale Grand Prix challenge in 1934.

To do so, HVA hired Woods and Nott to supplement the Swedish riding team, while Mannerstedt developed a 350cc version of the V-twin. But a major setback occurred when the truck carrying the five team bikes to the Isle of Man was dropped from a crane while being loaded on board ship at Gothenburg harbour, landing upside down on the quayside and badly damaging the bikes. To make things even worse, Mannerstedt was rushed off to hospital with appendicitis while supervising round-the-clock repair work!

However, Nott finished third in the 350cc Junior TT and Woods was headed for a certain second place in the 500cc Senior race, splitting Guthrie and Simpson on the works Nortons, when he ran out of petrol on the Veranda eight miles from the finish, after stepping off at Ramsey Hairpin and remounting, and having already set the fastest lap.

Subsequent races proved the Husqvarnas to be fast but rather fragile, though some good places were achieved in spite of Woods injuring his hand in a Spa Francorchamps crash. Tragically, Kalén was killed at the 1934 German GP, and that ill-fated HVA transporter caught fire in Holland en route back to Sweden, destroying five of the six bikes inside, with the only survivor thrown out onto the grass verge when a gas cylinder exploded! A single 500 was cobbled up from spares in the factory for Sundqvist to ride in the Swedish TT, which he won again.

For 1935 a new batch of bikes was constructed, with even less weight and more speed, but before they could be raced, the HVA board decided to withdraw from racing for economic reasons, instead entrusting the bikes to various riders to race on a private basis, with limited factory support under the Scuderia Husqvarna banner.

Just to show what might have been achieved, Sundqvist beat Karl Gall’s works supercharged BMW twin to win the Berlin GP on the ultra-fast Avus circuit, while a solitary works entry was made for Stanley Woods in the 500cc Swedish TT, which he also won – Husqvarna’s fourth consecutive victory in its home GP. But at the end of the season the bikes were sold off, and the factory race shop closed – yet in spite of the ensuing lack of development, the Husqvarna V-twins remained very competitive for the next couple of years, and even won races in the post Second World War era, when future Honda 50/125cc World Champion Luigi Taveri beginning his racing career riding one!

PRESERVATION SOCIETY

Today only a handful of these rare and exotic machines remain, three of them owned by Husqvarna itself which are occasionally lent out for demonstrations. In total, there are five original/authentic works 500s and two 350s, plus a number of engines, some of which saw duty in the back of Formula 3 racing cars in
the 1950s.

One of these bikes is to be found in the Sammy Miller Museum in Britain (www.sammymiller.co.uk) in the shape of one of the 1934 works 500cc V-twins damaged in the transporter fire at the end of Husqvarna’s tour of Europe that season, which Sammy and his faithful helpers Bob Stanley and John Ring reconstructed in the late 1980s.

To do so they used the original 64.9 x 57mm 498cc OHV engine, four-speed Sturmey-Archer gearbox, Amal carbs, HVA girder forks and various other components from the damaged bike that was believed to have been Stanley Woods’ Isle of Man Senior TT racer, fitted in a replica single-loop chassis built by Swedish HVA enthusiasts Gosta Svensson and Bo Friis.

Finished in the handsome maroon works 1934 race livery with black lining – the Swedish V-twins were painted silver and black all the other years they competed – the Miller Husqvarna made its public debut at the 1989 Festival of 1000 Bikes at Brands Hatch, and has since returned to the Island for Sammy to ride it in the TT lap of honour, as well as demonstrated by him at other historic bike events around Europe.

Having tested two of the Swedish V-twins as long ago as 1982 – Nott’s 350, still owned today by the Husqvarna Group in Sweden (which no longer has any connection with HVA motorcycles), and Sundqvist’s 1934 Swedish GP-winning 500, then owned by the late Curt Borgenstam, a noted ship designer to whom Sammy Miller pays tribute as an expert Husqvarna enthusiast who supplied invaluable data in helping John Ring rebuild the Miller bike’s 500cc V-twin engine – it was a pleasure to renew my acquaintance by riding Sammy’s bike at a local airfield and on the Miller Museum’s impromptu test track, which wends its way through the car park and access roads.

The Husky GP racer looks like a sort of junior vintage Harley, with the 50º motor’s only slightly wider included cylinder angle than H-D’s traditional 45º V-twin format. The dry-sump motor weighs a remarkable 27kg only, with its vertically split crankcases cast in magnesium, as are the rocker boxes – in spite of which, thanks to a minor miracle, they all survived the transporter fire intact without melting, although the screwed-on upper cylinder fins (only the bottom three are magnesium, and were undamaged) were distorted by the heat. In spite of the otherwise meticulous restoration, have been left in place as a mark of history.

The aluminium cylinder heads carry solid (not sodium-cooled, as was commonplace back then) valves sitting in bronze seats cast directly into the head, controlled by exposed hairpin springs, with the pushrods located up the right side of the cylinder. The twin one-inch Amal carbs sit between the vee of the cylinders, turned through 90-degrees so as to lie horizontal and thus offer a considerable degree of downdraught, in spite of the curved inlet tract.

The bottom end consists of a plain-bearing crank bolted to full-circle balanced flywheels, with steel 'knife-and-fork' Harley-type aluminium con rods. The whole assembly runs on roller main bearings on each side, with the external oil pump driven by worm gear off an intermediate pinion on the right, just under the chain drive to the Bosch magneto located in front of the crankcase, running off a spur gear in the timing case.

Primary drive is by chain to the separate four-speed gearbox, located under the base of the seven-litre horseshoe oil tank and controlled by an enormous rocking pedal of the type that was commonplace on Italian bikes post Second World War, and unusually for the period operates in the pattern first introduced in Germany, then copied by the Japanese and standardised on road bikes today, i.e. down for first and up for the next three ratios. It’s still a right foot gear change, though.

THE RIDE

Firing this priceless piece of Swedish racing history up produces a distinctive, offbeat, staccato rip from the narrow-angle V-twin’s long straight pipes. The one from the rear exhaust extends way back beyond the rear wheel in a way later banned by the FIM. Hopping aboard the V-twin Husqvarna feels surprisingly close-coupled by the standards of the day, with a short 1320mm wheelbase aided by good leverage from the wide-spread handlebars in helping steer the bike through the tighter turns of the Circuit de Miller.

Even more astonishing is the smooth, free-revving nature of the 50º V-twin motor – if I was expecting the shake, rattle and roll of any 45º Harley ever built I got a pleasant surprise. Husqvarna got the balance factor exactly right on this engine, which is as silky and vibration-free as a modern Ducati without, of course, the benefit of any balance shaft or offset crankpins, such as narrow-angle V-twin engine designers use today.

On the other hand, especially by the standards of the vintage era, the Swedish bike doesn’t have the torquey punch you’d expect from a V-twin – Folke Mannerstedt’s theories of radical camshaft design mean I have to rev the bike hard to obtain the remarkable 44bhp at 6800rpm available at the rear wheel, comparable to what a cammy early Sixties Matchless G50 single was putting out more than a quarter of a century later.

There’s no rev counter fitted, but while the V-twin motors smoothly out of a slow turn at low revs without a snatch, it’s not till I really wind it on that things start to happen faster. That’s when I discover that the Husqvarna has an impressive turn of top speed, especially if I work the positive-action gearbox hard to keep the revs dialled in. Kicking it up through the gears with my heel became second nature, especially changing up from third to top while stretched flat out over the 22-litre fuel tank at full arms’ reach, with my bum on the rear mudguard-mounted pad for a wind-cheating posture as practised back then.

The gearchange is quite positive and crisp, and although bottom gear is very low, there’s not as much of a gap between the top two ratios as was commonplace back then on other, perhaps more torquey bikes which used an overdrive top gear, a further confirmation of Mannerstedt having opted for a narrower power band and more radical cam timing, in pursuit of more top end power, and speed. Full marks, too, for cleanliness: in spite of the exposed valve springs, the Husqvarna was as clean and oil-tight as a modern bike, with no need to festoon it with sponge everywhere to mop up the oil spill, like on a classic-era Manx Norton!

By all accounts Husqvarna’s handling in general wasn’t considered in the same league as the British singles of 80 years ago, but Sammy’s bike coped okay with sweeping turns, and even rode the many bumps on his airfield test track quite well. There’s no rear suspension, but the sprung seat gives reasonable comfort, and the girder forks aren’t bad by the standards of the day, even if the front end flaps around quite a bit if I hit a bump on the angle, although the fat handlebar grips and wide bars do allow me to wrestle it into submission without having to shut off.

The thought of having to ride the bike in a four-hour GP race at this sort of pace over the rough road surfaces of the 1930s, fills me with admiration for Stanley Woods and his colleagues. Men of iron, especially when having to cope with the Husqvarna’s single biggest defect: the completely useless front brake, which being a mere 7in/180mm single leading-shoe design simply isn’t man enough for a combined rider and bike weight the wrong side of 250kg.

I remember both the 350 and 500cc bikes I rode almost 30 years ago at the Salzburgring in Austria had exactly the same problem: the only way you could make them stop was by standing on the back brake, and praying – both very hard! Use too much engine braking and the valves will bounce, so I plan ahead to stop, and use that back brake. On the loose surfaces of the day, this must inevitably have led to power sliding round turns – so is this why Swedish riders became so good at speedway?

Riding Sammy Miller’s historic 500GP Husqvarna road racer was a reminder that the transplanted Swedish marque already knew quite a bit about building bikes for on road use as well as off-road, even before the debut of the Nuda 900. But it also underlines that Sweden played a little-known part in the evolution of Grand Prix motorcycle design, in producing the first V-twin 500cc racer to taste top-level success.

Too bad that Husqvarna management's corporate nerve failed, just as its bikes were becoming truly competitive and well-sorted, for this left Italy’s Moto Guzzi to follow its lead in creating the glorious wide-angle 120º V-twin, which the Italian marque took to victory in the 1935 Isle of Man Senior TT, courtesy of ex-Husqvarna rider Stanley Woods! What might have been, if only?