Developed in 1950 by senior engineer Ernst Schmidt and introduced in 1951, the Zundapp model KS601 was produced in three versions until to 1958, with total factory output of some 5,600 machines. It was termed the Green Elephant (der Grüne Elefant) by Carl Hertweck of "Das Motorrad" in an early and very positive article due to its substantial torque and lime-green livery. The name stuck.
The KS601 was developed from the pre-war KS600 which was also briefly produced in the early post-war years. It features a tubular steel frame (replacing the pressed-metal chassis) and telescopic forks, and was the fastest German road bike of the day.
The KS 601 Elastic with swing-arm suspension was aimed at the American market, but at this time the motor car was fast overtaking motorcycle popularity both in the US and in Europe. The 601 was the swansong for Zundapp.
The Elephant Rally was established Stuttgart in the winter of 1956, and is held every year.
Reliability trials in Europe were frequently dominated by factory Zundapp team riders, and this greatly enhanced the model's popularity.
In 1951 the KS601 excelled at the international Austrian Alpine Rally with riders Hans Ernst, Gustav Keitel, and Georg Weiss, and the following year Ernst and Weiss won gold medals at the Six-Day Trials in Varese. All three won gold in 1953 and 1954, by which time they were lauded in the press as "The Elephant Team". Similar laurels were awarded to the team in the years up to 1960.