How the mighty do fall. DKW was once the largest motorcycle manufacturer in the world, but hard economic times in the German motorcycle market in 1956 led to the eventual demise of this once enormous, and very famous motorcycle factory.  DKW’s heyday was the 1930s, when it had grown from tentative steps in the late ‘Teens to produce small two-stroke bicycle motors of 122cc, to ride the wave of motorcycle popularity in 1920s Germany, to becoming the largest in the world by 1931.  This growth was ill-timed, coinciding with the Depression, but a clever tie-up with car manufacturers Audi, Wanderer, and Horch – creating Auto Union – saved all these companies, and placed them in an advantageous position for the economic revival of the mid-1930s.  DKW’s supercharged two-stroke racers of the 1930s were miracles of complication and development, with 5-piston ‘twin-cylinder’ supercharged twins taking wins on tracks all over Europe, including the Isle of Man TT in 1938.  DKW’s racing department had 150 employees in 1939, surely the largest for any motorcycle factory pre-war (and maybe post-war too!), although their brilliant work was dispersed during WW2, and the ban on supercharging by the FIM post-war.

The 1954 version of DKW’s 3-cylinder two-stroke racer, with one horizontal cylinder and two vertical. This is the first iteration of the second series machine, designed byHelmut Görg (‘George’ in English) in early 1954. [Paul d’Orleans]
Germany was banned from international racing competition until 1951, and their first racing machines for that season were single- and twin-cylinder two-strokes, designed by Erich Wolf.  Without forced induction, Wolf could not find the power he needed from his two-stroke, although he tried everything: disc valves, different piston shapes, different cylinder barrels and heads, and extreme light weight.  Fitting an expansion chamber exhaust made a big difference for 1952, and marked the beginning of the science of two-stroke tuning using exhaust resonance, which would reach its peak in the 1980s and ’90s, as GP racing became synonymous with the two-stroke howl.

The source of the din! An extremely compact, air-cooled triple. Note the hand-made nature of the whole machine: the rough welds for the frame and fuel tank, and the beautiful hand-hammered aluminum tank. [Paul d’Orleans]
DKW also unveiled a 3-cylinder machine in 1952, with two upright cylinders and one forward-facing horizontal cylinder, which had echoes of their extremely complex 1930s racers of similar architecture.  This time, the forward cylinder wasn’t a ‘ladepumpe’ supercharger, but a working unit, which required a few interesting tricks with the crankpin positions to deal with the fierce vibration inherent in two-stroke multis (a trick Japanese companies poached for their own two-stroke triples and fours).  The new motor had three 116cc cylinders, making a 348.8 capacity, and used a six-cylinder magneto from a BMW 328 for sparks, driven at half speed.  Three Dell’Orto 28mm carbs fed the motor, and 3 crude expansion chambers helped breathing,  while a 4-speed gearbox was kept within the small unit-construction crankcases, which fitted neatly in the chassis of the 250cc twin racer.

The devil is in the details! The triple air lever for the 3 Dell’Orto carbs, which apparently only August Hobl truly mastered. Love the hand-cut nature of this one-off device, with every file mark visible, and not polished out – because why bother on a racer? [Paul d’Orleans]
The 1952 3-Cylinder DKW wasn’t a huge success, although it looked promising, and had a good turn of speed, albeit without reliability.  Veteran DKW star Ewald Kluge took 6th at Solitude in front of 400,000 spectators, in spite of a broken shoulder blade after a fall, while Siegfried Wünsche took 7th at the Barcelona GP.  For 1953, designer Erich Wolf made changes for more power, and better reliability, including an oil pump for direct injection.  At the season-opening Isle of Man TT, he was seen testing his own machines at over 100mph in his rolled-up shirt sleeves, and no helmet! The 350 triple was an incredibly loud machine, as noted in the press of the day, as Motor Cycling notes: “Ouch! What an attack on the eardrums as No.90 Siegfried Wünsche’s DKW screams up to its high pitched war song!”  That ear-splitting noise was the basis of the racer’s enduring nickname, ‘Singende Säge’ (Singing Saw)… or chainsaw, if you prefer.

Rev-counter, clip-ons, steering damper, and very useful earplugs! Note smooth fork triple clamps, fuel tank breather hose, and very hand-made fuel tank. [Paul d’Orleans]
The 3-cylinder racer needed a redesign to be competitive with the best of Italy in the mid-1950s, and luckily, the factory was in a position to invest money in racing.  Sales of DKW motorcycles and cars were booming in Germany’s ‘economic miracle’, and its workforce had doubled to 10,000 between 1950 and 1954.  That year, Robert Eberan von Eberhorst was hired as Technical Director, after a stint at Aston Martin and BRM, and he transformed the racing department by putting Helmut Görg in charge of all racing activities.  It was decided that the 3-cylinder racer held the most promise for GP success, so the single- and twin-cylinder two-strokes were dropped, and Görg himself totally redesigned the engine from first principles.  The new crankcase was narrower, for better gas compression, and the flywheels of the six-piece crankshaft were full circle to further increase internal compression.  Flat-top pistons were used instead of Wolf’s deflector pistons, and the cylinder heads used a squish band for better combustion.  The length and shape of the expansion chambers was recalculated, and it was found that among the most critical pieces of tuning was the location of the rubber-mounted float chambers feeding the Dell’Orto racing carbs.

A new magnesium 2LS front brake for ’54: by the next year enormous hydraulically-operated brakes were used. Note the short leading-link forks, with springs inside the fork leg, and the hydraulic damper rod external. The brake hub has a shrunk iron liner inside an aluminum half-hub, while the ‘other’ half of the hub is magnesium, as is the brake plate. Note also the grease nipples for teh axle and brake arm pivots – extravagant (and very German) details for a machine only running for a few hours at a time for the longest races (ie, the Isle of Man TT).  [Paul d’Orleans]
The new engine had a reduced maximum RPM (10.5k instead of 12k) for more reliability, the ignition was switched to a coil and points, the gearbox gained a cog for 5 speeds, and the front fork was changed to a very light, and very strong short leading-link item, with stronger magnesium brakes.  Unusually, each carb was equipped with an independent air slide control controlled via  three levers mounted on the left handlebar.  It was said only one rider was truly capable of using these levers: August Hobl, who took the 350cc German Championship in 1955, and took third in the 350cc World Championship.  That year the magnesium brakes grew larger and were hydraulically operated, and the machine was equipped with an aluminum ‘dustbin’ fairing. For 1956, the 3-cylinder racer was further refined, giving a reliable 46hp at 9700RPM, and a top speed of over 140mph. Hobl took second place in the World Championship, but hadn’t ridden in every Grand Prix, as the German motorcycle industry was in a crisis, including DKW.

Jelly mould! Hand-hammered fuel tank to suit the rider’s knees and arms, and help with flow to the rubber-mounted float bowls. Note the fuel taps, front and rear, with deep reservoirs for both to ensure good fuel flow for front and rear float bowls.  The twin rear carbs shared a float bowl. [Paul d’Orleans]
1956 should be considered ‘the year the music died’, as the disastrous state of the European motorcycle industry led the premier factories to halt Grand Prix racing: DKW, NSU, BMW, Gilera, Moto Guzzi, etc.  That left the field wide open for MV Agusta, the private fiefdom of Count Domenico Agusta, who seemed to regard production as an afterthought to his first love – racing.  DKW never entered another Grand Prix, as in common with every other German motorcycle producer, they had greatly over-estimated future sales at a time the public was finally able to afford small cars.  DKW happened to produce these too, which kept the company afloat while others brands were failing, but motorcycle production was transferred in an amalgamation of the DKW, Victoria, and Express brands under Daimler-Benz, creating a new company, Zwierad Union in 1958.  While motorcycles were still sold with the DKW badge for many years after, the proud years of DKW as an independent company with a tremendous racing lineage were over.  They built an estimated 519,000 motorcycles after WW2, and had once been the largest motorcycle company in the world: now we have incredible machines like this 1954 Singing Saw to remember them by.

Have a go? 143mph from a 350cc was really going in 1956. Love the ergonomic fuel tank shape for ‘tucking in’. The flat seat is pre-bump-stop saddle. [Paul d’Orleans]
The machine in these photographs is part of the Hockenheim Museum Collection.  It has been fully restored to its original specification, and is regularly demonstrated at vintage racing events in Europe, where a new generation of fans can learn the meaning of ‘ouch!’, and understand why earplugs are kept in the lightening holes on the steering damper knob!  It’s the original 3-cylinder two-stroke beast, a mantle taken up in 1969 by Kawasaki’s H1: the howl of three two-stroke pistons working in unison is not easily forgotten!

August Hobl aboard a ’54 DKW triple of this specification, in a slightly later form, with bump-stop seat, and larger rear wheel fairing. Note the fuel tank is slightly larger – apparently each machine had 11 fuel tanks of different capacities, to suit different circuits! [Hockenheim Archive]
The magnesium SLS rear brake and hub, which is all-magnesium, unlike the front brake. [Paul d’Orleans]
The back side of the front wheel hub, showing the leading-link fork to advantage. It’s an extremely light and very stiff design, although wheel travel is limited to the length of the link’s arc. This fork probably has about 4″ of travel, while most road-goin short leading link forks have 2″.  [Paul d’Orleans]
Beautiful shapes on the hand-beaten alloy tank.   Note the locking fuel cap, and the architectural braces for the front brake torque arm support, and pivot support for the fork link, which must of course be of identical length.[Paul d’Orleans]
The rear fenders creates partial streamlining, although the dustbin fairing was used for the whole team in ’55. [Paul d’Orleans]
The view most other riders had of the DKW 3-cylinder racer, which was lightning fast. [Paul d’Orleans]