Walter Kaaden, left, invented the expansion chamber exhaust. In this photo, he’s chatting with legendary motorcycle journalist Vic Willoughby.
The last Backmarker, focusing on the Nazi’s use of the 1939 Senior TT
for propaganda purposes, reminded me of another time that motorcycle racing was used for propaganda.
After Hitler’s surrender, Germany was divided into occupation zones, with the Russians in control of the eastern part of the country. Within a few years, the Russian sector of Germany, along with the rest of the East Bloc countries, had been sealed off by the so-called Iron Curtain.
Western Europe set about rebuilding the industries that had been shattered in the war. In the 1950s, the metallurgical, engineering and manufacturing breakthroughs that had been developed when the western economies were on a war footing were adopted by civilian industry. Concepts that were largely un-buildable for pre-war engineers became feasible, and racing motorcycles advanced rapidly. And over in Japan, Honda was producing better and better race bikes as well. Of course, technological advances weren’t limited to motorbikes; the world of automobiles was changing fast, too.
Behind the Iron Curtain, however, Soviet-style centralized ‘planned’ economies put almost all their engineering talent to work on military projects. The result was that civilian vehicle production lagged, and development was almost non-existent. Look up the East German ‘Trabant’ car for an example of just how ghastly their vehicles were. And as bad as they were, ordinary workers still had to wait years to get one.
In spite of that, motorcycle racing remained fantastically popular in Communist countries. In the post-war period, the East German Grand Prix drew hundreds of thousands of fans. They had local heroes to root for, because there was an exception to the general technological backwardness of the Communist Bloc: the East German MZ Grand Prix team. ‘MZ’ stood for Motorradwerk Zschopau, which is translates as ‘motorcycle factory Zschopau.’ The factory in the town of Zschopau was the original home of the DKW brand.
In the late ‘50s and early ‘60s, the East German GP drew the largest crowds in motorcycle racing history. The trackside banners read, “Go MZ”.
What a team MZ was in the late ‘50s and early ‘60s. Beginning in 1953, the MZ race shop was under the command of one of the true geniuses of our sport – Walter Kaaden. Kaaden was literally a rocket scientist, who worked on the Nazi V-2 rocket program. Many of the Nazi’s rocket guys were spirited away to U.S. missile programs at the end of the war, and in a slightly different world, Kaaden may have ended up here alongside Werner Von Braun. But he stayed in East Germany; unlike many of that country’s citizens who were held in check by one of the world’s most feared secret police services, he was an enthusiastic supporter of the Communist regime.
After superchargers were banned from Grand Prix, Kaaden developed MZ two-strokes that combined disc valve induction with expansion chamber exhausts. The exhausts, in particular, were essentially Kaaden’s invention. (There were some pre-Kaaden exhausts that took the general bulbous shape, but only he understood the principles of resonance, pressure waves and all the stuff that made them work). It is impossible to overstate the engineering impact of the expansion chamber. In 1954, MZ engines produced about 100bhp per liter. By 1961, they produced 200bhp per liter.
The success of MZ in Grand Prix racing was an important element of East German propaganda. While the marque was justifiably proud that the very best riders of the day (Hailwood included) lined up to ride their 125 and 250cc racers, they also groomed a home-grown Communist star in the form of Ernst Degner.
Then, in 1961, with Degner poised on the brink of stardom, the East German defected while competing at the Swedish Grand Prix. Within hours he was on his way to Japan, where he signed to ride for Suzuki. At the time, there were rumors that he’d escaped with a complete set of drawings or even a disassembled motor in his luggage. That needn’t have been the case; Degner was not just a wrist, he was a trained engineer who had played an important development role at MZ. The contents of his helmet were damaging enough to the Communist cause.
In 1962, Degner gave Suzuki engineers a running start by bringing them the secrets of the two-stroke expansion chamber.
Degner won the 1962 50cc championship on a Suzuki that bore a distinct resemblance to an MZ. The following year Hugh Anderson won on a Suzuki 125, and another Japanese brand was away to the races.
My friend Michelle Duff (as Mike Duff) raced against Degner, once rode a factory MZ 125cc GP bike, and even visited the factory. She’s told me stories about the Continental Circus making trips into Communist Europe, to race in East Germany, Yugoslavia, and Estonia. The riders got paid in currency that had essentially no value in the west, so they had to find a way to spend it on stuff they could buy on the Communist side and resell later. That was a problem since few consumer goods made there were any good. Crystal and optical goods like cameras and binoculars were popular choices, and often had to be smuggled back to avoid duties.
A few years ago, I wrote Michelle to ask her about Degner, and this is what she remembered...
“Yes, I knew Ernst Degner. I think I first met him in 1961 at the Swedish GP at Kristianstadt. The next year he rode a phenomenally fast 125 Suzuki Twin that had a lot of MZ technology attached to it. He rode for Suzuki for a number of years, and I think it was in 1963 at the Japanese GP that he crashed and he was knocked unconscious.
“His bike caught fire. All the marshals were standing back not wanting to go into the flames, but Hugh Anderson ran in and pulled Degner to safety. He was badly burned over much of his body, including his face. After many skin grafts, he raced again.
“He was always a very dedicated rider and a very private person. Perhaps his East German upbringing did not allow him to trust anyone. Not that he was a hermit or anything; he was friendly to me and we talked as one rider to another, but being on different teams we did not share secrets or emotions.
“I rode an MZ 125 once, at Sachsenring in the East German GP. Sachsenring was a road circuit like most European GPs. The section through the village of Hohenstein Ernsthal was all cobblestones and quite slippery in the wet. From the town, the road had been freshly paved and was a treat to ride. It paralleled the Autobahn, which was temporarily closed for use as a parking lot. For about two miles there was nothing but bikes and cars parked along it. About 300,000 people used to attend the event. I remember in 1966, the organizers were worried on Saturday because attendance had been down to 225,000 spectators, but on Sunday they were happy when just over 300,000 people entered the racing complex.
“The original Sachsenring course must have been 8 or 10 km around. The new Sachsenring, the course the MotoGP guys use today, uses the same uphill tight left switchback hairpin and start finish area as the old one, but immediately past the start-finish line the new course turns sharply right and is all new. The stretch of road that we used to get from the start-finish area to the paddock (where we used to work on our bikes and camp) is now filled with modern car dealerships. The roads that made up the old circuit are all still there, but they’re hard to recognize amidst all the new construction.
“I only went to the MZ factory once and do not really remember it. That was in 1966; I had fitted a homemade twin disk setup to my RD56 Yamaha Twin (the one the factory lent me to ride privately for the season). I was using two Mini Cooper calipers sawed in half with a solid aluminum plate across the back to support the inside brake pads. Because of limited space between the forks for a twin caliper system, the triangulation of the spokes was very limited. At the center hub, the two sides of the spokes were only two inches apart.
“One of the MZ mechanics was looking at my set up and worried there would not be enough support for the wheel. He offered to rebuild my front wheel and give me another centimeter of spoke triangulation. So I took the wheel over to the MZ race shop and in about 30 minutes they rebuilt my front wheel with new spokes; sure enough I had a much stronger wheel with the additional triangulation.”
“Degner Curve” at Suzuka is named after him. Degner’s post-racing career was sparsely documented, and he’s been dead over 20 years now, so his trail’s grown cold, but I have read that Degner returned to Germany (albeit West Germany) where he provided in-service technical training to Suzuki dealership staff.
While the vast majority of MZ production capacity was devoted to the manufacture of plebian two-strokes for day-to-day transport, the race bikes were things of beauty. Click here
to see an example on Flickr.
According to Wikipedia, he later ran a rental car business in Tenerife, on the Canary Islands. His death was probably caused by an accidental prescription drug overdose, but there have long been rumors that he committed suicide, or even that he was murdered by the Stasi (the East German secret police.)
Degner did not live to see the fall of the Berlin Wall, which would have allowed him to return freely to his home in the former East Bloc. Kaaden, however, was a good Communist all his life, even after German reunification. He never forgave his star rider’s betrayal. He died in 1996. After 90 years as a motorcycle factory, the original DKW-then-MZ works in Zschopau finally closed in 2008, and became a night club.
Now that the last of the MotoGP support classes have converted to four-stroke power, Kaaden’s record of two-stroke innovation is starting to read like ancient history. Still, the switch from 500cc strokers to 990cc “diesels” in MotoGP was merely a reflection of the fact that all big road bikes use four-stroke power. (The last big two-stroke I can think of was, yes, a Suzuki – the excellent GT-750.)
I wonder if we abandoned the two-strokes just when technology like Orbital’s direct injection system promised to make them viable again. The day may come when (with better mileage and less pollution thanks to direct injection) two-strokes make a return in road bikes. If it happens, they’ll almost certainly sport expansion chambers based on stolen Cold War secrets.