Generally, upon seeing a Zundapp KS601
for the first time, folks ask "What kind of BMW is that?" It can be difficult to convince them
that, while BMW's success with the opposed twin did not escape the attention of Zundapp's
engineers, the KS601 and its ancestors evolved exclusively on Zundapp-Werke drafting tables.
They should really ask, is that the Zündapp KS 601?
A Little History - The KS601's Predecessors
Zundapp-Werke was an established company before venturing into the world of motorcycles
in 1921, having produced detonators for explosives since its founding in 1917. The company's
original name was Zunder-Apparatebau-GmbH. The name Zundapp was the union of the words
zünden, to detonate, and apparatebau, apparatus. If I recall correctly their
specialty was bomb fuses.
Production of the Zündapp KS 601 sprung from a bomb fuse factory.
Owner-industrialist Fritz Neumeyer also had the vision of offering a reliable high quality
motorcycle under the Zundapp name. He succeeded to the point that Zundapp was producing
more than 28,000 motorcycles per year by 1929. Things didn't go so well during the world
depression but Zundapp held on and emerged in 1933 with a host of new models designed by
engineers Richard and Xaver Küchen, including the K models. The fledgling K series
included opposed twins of 400 and 500 cc nominal displacement, and opposed four cylinder
motors of 600 and 800 cc's, all flat heads. The 1933 K500 produced 12.5 HP while the K600
and K800 boasted 16 and 20 HP respectively, both at 4300 Rpm.
His desire to build a reliable inexpensive bike resulted in the Zündapp KS 601.
The products of Zundapp-Werke's Nürnberg-Schweinau plant, these bikes embodied many of the
features that would define the KS601 including shaft drive via a novel duplex chain drive
transmission, although these early versions were stick shifts. They were considered by many
to be technically superior to their contemporaries and soon earned a reputation for endurance
These bikes had many of the features of the Zündapp KS 601 that would follow.
In 1935, the year the firm's founder died, Zundapp introduced the KS500 model, or Kardan
Sport 500. Kardan referred to the U-joints on the shaft drive and sport referred to the
new overhead valve motor which produced 24 HP at 5200 Rpm. Like the KS601, these motors
had cast iron cylinders, aluminum heads and valve covers, with a carburetor on each
cylinder drawing air through a single filter beneath the upper engine cover. Also, these
were the first Zundapps available with a foot shifter.
These motors had cast iron cylinders like the Zündapp KS 601.
In 1938 the KS600 was brought into production. The cylinders shared a single carb but
the motor developed 28 HP despite that. 18,000 KS600's were built between 1938 and 1940
with most going to the armed forces. These bikes retained the girder front suspension,
apparently with friction dampers although air/oil shocks were played with at some earlier
Telescopic forks were introduced with the Zündapp KS 601.
With war immanent the Zundapp factory jumped headlong into design of the super heavy KS750
which entered production in 1941. Intended strictly as a sidecar machine the KS750's
conventionally geared transmission, as opposed to the hallmark Zundapp duplex chain tranny,
was shifted via two hand levers on the side of the gas tank. Another controlled a differential
which in normal operation delivered 60% of the torque to the bike's rear wheel and 40% to
the sidecar wheel and could be locked when negotiating difficult terrain.
This differed from the Zündapp KS 601's duplex chain drive.
Sectional View of Zundapp KS601 Engine and Duplex Chain
Drive Transmission. Click image for
larger view, 94KB.
The Zündapp KS 601 engine and duplex chain transmission.
Starter Bevel Gears
Clutch Lever Bar
Duplex Chain Drive
Multiple Disc Clutch
Universal Joint Shaft
Clutch Thrust Bearing
Oil Drain Plug for Engine
Oil Filler Screw for Gear Unit
To fully dispel the myth that Zundapp is a derivative of BMW, much less an inferior copy, the
heavy sidecar KS750's were so superior to BMW's offering that the German government compelled
BMW to copy the important technical details, against their strident protest.
The Zündapp KS 601 was pretty rugged in its own right.
From 1942 the KS750 was the only motorcycle Zundapp built with total production exceeding 18,000
units. During the war the factory also built aircraft parts, bomb fuses, and other ordinance.
It was basically bombed out of existence toward the end of WWII. After reconstruction of the
buildings production focused first on grain milling equipment, then sewing machines. Motorcycle
production did not resume until 1947, mostly dedicated to smaller displacement sidecar machines
to fill the need for inexpensive transportation in post war Germany.
The Zündapp KS 601 wasn't introduced until 1950.
Next - The KS601 Arrives on the Scene
Acknowledgements & References