Viking V-twins
Racing test of the 350 and 500 cc Husqvarnas
Sweden is not a country normally associated with the manufacture of exotic road racing machinery, but during the first half of the 1930s the country's largest motorcycle producers, Husqvarna, created a series of Grand Prix V-twins that not only seriously threatened the established Norton and Velocette teams, but also broke new ground in terms of materials and engine design. A total of 19 V-twin 500s were built by Husqvarna between 1930 and 1935, matched by a shorter run of four 35Os. Handled by riders of the calibre of Stanley Woods and Ernie Nott, as well as Swedish stars such as Ragnar Sunnqvist and Gunnar Karlen, the Scandinavian machines were an important part of the classic GP scene in the 1930s, reaping many successes for the Swedish equivalent of BSA and FN
Ironically, it was FN which provided the impetus for the Husqvarna racing effort, thanks to the experience gained by a young Swedish engineer in assisting the Belgian factory with their world record attempts on a frozen lake in his home country in 1927-28. His name was Folke Mannerstedt, and his work at FN convinced him of the importance of a number of factors relative to high performance motorcycle design, which nowadays we take for granted, but were then, but notional theories.
Chief among these was the use of wild cam timing to achieve extended valve, opening periods, better breathing, and 50% more power higher up the rev range, at the expense of increased valve overlap and thus less bottom-end poke. He coupled these theories with the harnessing of exhaust resonances to improve cylinder filling and thence combustion. Additionally, Mannerstedt was fanatical about 'adding lightness' and thus improving the originally cumbersome V-twins' power to weight ratio. Thanks to the extensive use of light alloy and magnesium, he was able to reduce the dry weight of the 500 from 385 lbs in 1930 to a remarkable 272 lbs by 1934.
Mannerstedt joined Husqvarna in 1929, inheriting a 730cc ohv V-twin engine designed by Harald Toller for the factory in 1926, and used chiefly for sidecar work. Originally, Mannerstedt simply scaled down the unit to make a 500cc version for use in the ISDT, but after that he so completely re-developed the basic design that the eventual GP machine may really be considered to be his own work. Like its predecessor a narrow-angle, 50-degree, ohv V-twin, this first appeared in 1930, but was not seriously raced until the following year.
Versions in 250 and 350cc sizes followed, originally single-cylinder machines employing a single pot on the V-twin crankcase with the other mouth blanked off, although for 1934 Mannerstedt scaled down the 500 twin to produce the first 350cc multi to appear on the GP scene. But it was the 500 which shone first, with Sunnqvist defeating the works Norton team in the 1932 Swedish GP at Saxtorp to register the marque´s first major international win, with team-mate Karlen second.
  
A 1934 350cc racer from the Husqvarna museum     The Huskvarna stable from the mid ‘30s

Further development lowered weight and increased power during the 1933 season, with commensurate success, so for 1934 the Husqvarna management decided to launch a serious attack on the classic GPs. Recognising that their own riders lacked experience on courses such as the Isle of Man and Spa, they engaged the services of Woods and Nott, but their careful preparation for the campaign suffered a setback when the lorry carrying the five team bikes was dropped from a crane while being loaded onto the Isle of Man ferry. The machines were badly damaged, and to make matters worse, Mannerstedt was rushed to hospital with appendicitis while supervising the round-the-clock repair work. The team eventually arrived late in the Island, in time for Ernie Nott to score a stirring third place in the Junior behind the Nortons, with Woods battling for second in the Senior TT until he ran out of petrol at the Verandah on the last lap, having stepped off just beforehand at Ramsey Hairpin and remounted.
Though the 500s proved out of luck in the races that followed, the 350s showed themselves reliable and competitive by scoring a string of runner-up results in the GPs that year. But Karlen was killed in a freak accident in Germany, and to end the campaign on a disastrous note the ill-fated lorry caught fire on the way home to Sweden, completely destroying the machines inside. A single 500 was built from spares for Sunnqvist to ride in the Swedish GP in September and to compensate for some of the bad luck the team had suffered that year he won at record speed, following up with another victory the following week in the prestigious Gotlands TT.
Meantime Mannerstedt had been working on a revised, even lighter version for 1935, with gear-driven magneto, revised cylinders with extra finning, and megaphone exhausts. Construction of the new bikes was almost completed when the Husqvana board decided to pull out of racing in the spring of 1935: road bike sales were dwindling in a recession in the Swedish motorcycle market, and a 1000 cc V-twin built to capture lucrative Swedish government contracts (at that time in the hands of Harley-Davidson) had proved disastrously unsuccessful due to a high rate of cylinder wear.
A solitary factory entry was made for Stanley Woods to race in the Swedish GP that year, which he won, but for the rest of the season the machines were entrusted to private owners who banded together to call themselves Scuderia Husqvarna. The bikes were then sold off at the end of the year. In spite of the consequent lack of development and factory backing, the V-twin Husqvarnas remained extremely competitive for the next couple of years, and were actually raced successfully after the war. MV and Honda world champion Luigi Taveri even began his racing career with one in the 1950s!
Today only a handful of these rare and exotic machines remain. Four 500s and two 350s (one of each type) survive, plus a number of engines (including an incomplete 500cc unit in Britain), some of which saw duty in the 1950s in Formula 3 racing cars. It was thus of considerable interest when no less than four complete bikes appeared at the Old-timers' GP at Salzburg last September..
Seeing the bikes for the first time it is remarkable how much they look like scaled-down Harley-Davidsons. With only a slightly wider included cylinder angle than the H-D's traditional 45 degrees, the Husqvarnas are nevertheless much smaller in the flesh than they look in photographs - wheelbase of the single downtube rigid frame is only 52in. Mannerstedt evidently designed the bikes with a keen eye to making the basic layout as light and compact as possible, which explains how the 350 was so successful.
Husqvarna's act in buying up three of their ultra-rare former GP bikes, then farming them out to enthusiasts to maintain and display in use is an admirable lead that should be followed by other factories, not least the Japanese companies. Thanks to Husqvarna's initiative, those of us who never saw one of the most advanced and technically interesting designs in GP history in action in its heyday can admire Folke Mannerstedt's creations today.