DKW kicked butt with a three cyl. two-stroke

[Fire-medic]

Content courtesy of research by Paul d'Orléans

Want to go fast, really-fast? In Germany in 1955, after coming in 3rd in the 350cc World Championship, DKW used what they had learned to make a new variant on their World GP roadracer. It developed 46 HP at 9700 rpm, and was capable of over 140 mph. It was one of the first two-strokes to truly utilize a tuned expansion chamber. The engine used flat-top pistons and the cyl heads had a squish-band, similar to the Japanese two-strokes of the end of the 1960's, and through the 1970's into the 1980's. Kawasaki's fearsome 500cc two-stroke triple was released as a 1969 model, this DKW in its first design, pre-dated that by 15 years. Its exhaust note is punishing to the ears, even today as it regularly is run on exhibition in Europe. It's nickname: Chainsaw.

DKW factory rider August Hobl took second place in the 1956 350cc World Championship, despite not campaigning in every race.

Note the 'two-up, one down' position of the cylinders. The engine had a 5 speed transmission, and check-out the leading-link front end. It has external damping rods, and the springs are inside the larger tubes. The front brake had a finned aluminum center with a shrunk-in iron wear surface, and the brake backing plate and the opposite side plate were magnesium. It was a twin leading shoe design.



No paint on the tank, like Moto Guzzi and their famous Grand Prix V-8, "paint weighs something." So, eliminate it. As bare metal, the keen observer can see the hand-formed metal comprising the gas tank. Also notice the two fuel taps, one front and one rear. Just forward of the front fuel tap, is the remote, rubber-mounted float bowl. The position of the float bowl was found to be a critical design component to produce the most power. The two rear cylinders shared a common float bowl. Also, the tank was formed to provide room for the rider's knees and arms to tuck-in helping with reducing aero drag for more top-end.

The front brake.



How would you like to try to master this device? It's the air feed to the three Dell'orto carburetors! DKW had only one rider capable of putting this to its best use. Anyone raised on two-strokes knows how-sensitive they are to seizing, if an air leak happens: worn crank seals, a loose carburetor manifold, a leaky head gasket. "They always run best just-before they seize!" Sensing the impending doom, the racer who had a quick clutch hand might be lucky-enough to pull-in the clutch to prevent a spill as the engine locked-up. In racing, the DNF list was filled with those whose clutch-disengagement skills were too-slow.

 

[Krohsis]

It's nice to see someone else that is a two-stroke lover. Thanks for the detailed post. The air/fuel mix levers are pretty cool. But man, your spidey senses need to be on fire to make sure you don't get one cylinder just a touch wrong, especially if you are running at the ragged edge.

 

[Fire-medic]

your spidey senses need to be on fire to make sure you don't get one cylinder just a touch wrong, especially if you are running at the ragged edge.

Read the article, and it says there was only one rider on the team who could master the use of the air controls to effective use.

 

[Krohsis]

Read the article, and it says there was only one rider on the team who could master the use of the air controls to effective use.

Oh, I read the entire article (actually saved it) and saw that.

 

[Fire-medic]

So much history in racing! Then you saw where at one time, DKW was the world's largest manufacturer of motorcycles. Just like Birmingham Small Arms, (BSA) was 100 years ago. Their logo is three rifles resting together in a triangle/conical shape.

 

[Fire-medic]

When my two-strokes were getting ready to hit reserve, you could actually hear the engine pitch change slightly as the flow leaned-out.