Zundapp K800
Desert dueller
The name Zündapp comes from an abbreviation of Zünder Apparatenbau, meaning Detonator Apparatus, and the company that adopted this name in Nuremburg in 1917 was indeed a manufacturer of detonators for explosives, of which there were quite a few in use at the time.
However once the last shots were fired in WW1, demand for such things and weapons in general went into rapid decline, and 1919 all shares in the company were acquired by one of the original partners, Fritz Neumeyer, who had many and varied business interests in Germany. The factory’s output was initially switched from detonators to starter motors and alternators, and in 1921, to motorcycles. The new company’s first product – named the Z22 – was shown at the Berlin Automobile and Motorcycle Exhibition of 1921. A basic utility two-stroke design of 211cc called Motorrad fur Jedermann (Motorcycle for Everybody) and closely based on the British Levis, 1,500 were built in the first year of production and by the end of 1924, 10,000 had been sold. In 1925, a new 250cc model was introduced on a new production line that churned out 25,000 by 1928. Neumeyer decided it was time for more modern premises, which were built in Nuremburg, with a staff of 1,540 on the shop floor and in administration. 60,000 of the 250 models were built in 1928 – an increase of 267% on the previous year.
Then along came the Great Depression, but Zündapp powered along with their reliable and affordable motorcycles, of which 100,000 found owners in 1933. The latest models featured pressed steel frames made in-house and demand continued unabated. Zündapp had risen from nowhere to become one of Germany’s top motorcycle manufacturers. Totally new designs appeared in 1930, including the S500 and SS500 overhead valve models which were initially powered by English Rudge Python engines. As a reciprocal gesture, the Zündapps were sold in Britain as Newmounts. One business decision that backfired was the diversification into car manufacturing, using a design from Ferdinand Porsche called the Volksauto. This used a rear-mounted five-cylinder water-cooled radial engine with the bodywork made by the Reutter company in Stuttgart, but early testing results were so disappointing that Neumeyer scrapped the project before it could consume all his resources, and handed the manufacturing rights to Porsche. As the Depression began to ease, Zündapp forged ahead with new motorcycle designs which were shown at the 1933 Berlin Motor Show. The new range included what was known as the
K-series (K standing for Kardanantrieb, or enclosed powertrain – shaft drive). What had become a signature of Zündapp motorcycles, the pressed steel frame, was used throughout. Models included 400cc and 500cc twins, and 600cc and 800cc fours, all sidevalve ‘boxer’ designs, plus 200cc two strokes. By 1937, Zündapp held over 20% of the German market and produced its 200,000th motorcycle a year later. But the shadow of the forthcoming Second World War began to fall across the country, and the Wehrmacht became Zündapp’s biggest customer, in fact its only customer. During the duration of the war from 1939 to 1945, almost 40,000 of the Zündapp K-series models were manufactured for military use, not just for Germany but also for allies of the Axis powers.
A battle survivor
The featured motorcycle is a 1934 K800, owned by Hans Sprangers in Sydney. In his native Holland, Hans collected three such machines, two of which were sold to finance the restoration of this one. Despite his affection for the Zündapp marque, Hans is under no illusions about the 4-cylinder design. “Initially it was for civilian only. It was basically not a success. They dropped the model after only a few thousand were made because of the high cost and the unreliability, and developed the new overhead valve twins. These K800 seized all the time because the oiling system was wrong. Basically, the design had a paper oil filter at the end of the lubrication system, after the oil had been through the engine. This was fed to the filter through a very small hole and this was supposed to create enough pressure to force the lubricant through the engine, which it didn’t. The solution is to blank off the outlet and relocate the filter to the inlet side, leaving the oil in the engine to disperse in the block. Also, the original design used roller bearings in the engine and this was changed to slipper type. I have seized this one a few times (before we found the solution to the underoiling) because the rear cylinders get incredibly hot. Despite putting finned aluminium cooling rings on the exhaust flanges, the pipes still get so hot they burn the paint off. There are all sorts of things added to direct air over the engine, like the vanes off the front down tubes and the air scoops over the pipes, which are also to help prevent your legs from getting burned. I fitted an oil temperature gauge on the right side of the crankcase so I can keep an eye on it, and there’s an oil pressure gauge on the left side frame down tube.”
“Still,” he continues, “The engine design is a neat piece of work – a unit block construction engine/gearbox and drive shaft design, with no external chains or oil lines. This made them very suitable on dirt roads and in rough terrain as sand could not get into the drive gear. The Bing carb is only 18mm to feed all four cylinders and sits at the back above the gearbox and feeds through a manifold that sits under the big alloy casting on top of the engine. Some of these bikes came with Pallas carbs. It has massive amounts of torque but not a lot of power, only about 20hp.”
“The gearbox is four-speed with a hand shift. Actually it is not strictly speaking a gearbox in the conventional sense because the ratios in the box are all individually chain-driven. It’s unusual but it works well and requires virtually no maintenance. This was a feature of all the flat twins and fours. When the Second World War was on, the K800 was found to be too expensive and the overheating problems could not be solved so they went to the overhead valve twins (KS750) which were very successful. BMW was forced by The Wehrmacht to build the R75 based on the Zundapp. The KS750 is considered to be the better bike. But the K800 is still a nice motorcycle to ride, with a low, upright seating position, and is reasonably comfortable. The handlebars are very wide to give extra leverage for steering with the sidecar that was usually fitted – the sidecar wheel was not driven on this model. The steering is precise and the bike goes where you point the nose. In solo form it has great handling on winding roads, but if you get too confident and fast you risk grounding the footpegs on the road. The front forks have a hydraulic damping mechanism on the top link. ‚
The gear shift is a car-like H-pattern controlled by a long stick. All controls, other than the left-hand clutch) are on the right hand side.
Few of the K800s came to Australasia. I know of one other in Melbourne and two currently being restored in New Zealand. This particular bike is very original. The rubber Drilastic seats are in excellent condition despite the fact that they are 87 years old. The pillion seat has an adjustable friction damper that can be set for the weight of the passenger. It has the correct Veigel barrel-type speedo – these are extremely rare and can bring up to $5,ooo, if you can find one!”
“There are four separate stands for the bike – the lower front mudguard bracket hinges downward to support the front wheel (which is interchangeable with the rear), there is a normal centre stand under the engine, a rear stand and even a side-stand. This is a really interesting design that has a foot-operated latch. When you press on the latch the alloy footboard hinges down from the front and becomes a side-stand. Production stopped in 1939 when the factory switched to the K750 overhead valve twins with driven sidecar wheels. During the retreat of the German army on the East front through Russia and Poland, supplies were not coming through. Many vehicles were left behind as they simply ran out of fuel and the soldiers abandoned them and continued on foot. Many were picked up by local farmers and stayed in Eastern Europe. They were often repaired with Russian parts to keep them going. Only after the fall of the Iron Curtain did some come to
Western Europe.”
“I purchased this bike in Poland where it had been abandoned – dismantled and missing some parts. I rebuilt it over a period of nearly ten years. There is no workshop manual and knowledge about these bikes is scarce. Much of the engine work was done by Adrian Vergison in 2012 and has been in regular use since. Hans says that the oiling problems that causes the seizures have been largely eradicated, but not without some grief. “With the oil pump at the front, the rear cylinders were last in getting oil for lubrication and this led to more issues. Engines typically lasted not more than 2,000km which was obviously unacceptable. The factory made numerous modifications and went back and forth from roller main bearings to slipper bearings, and back again.” Hans recalls grinding to a halt with a seized engine in the 2015 Veteran and Vintage rally in Canberra – an embarrassing moment that resulted in him receiving the ‘Hard Luck” award. Nevertheless he says, “These are wonderful bikes with a great deal of history attached.”