1973 Advert for a German made Zündapp motor bike.

"The first Zündapp motorcycle was the model Z22 in 1921. This was the Motorrad für Jedermann ("motorcycle for everyone"), a simple, reliable design that was produced in large series. Zündapp's history of heavy motorcycles began in 1933 with the K-series. The "K" refers to the type of drivetrain that these models used, 'Kardanantrieb' meaning enclosed driveshaft with two universal joints."

Text source and more info: http://en.wikipedia.org/wiki/Zündapp

Image source: http://www.returnofthecaferacers.com/2011/12/retro-cool-motorcycle-adverts.html