No worries.
They were Revell AG tie ins with a German comic character called Werner. The figure is modelled after the author, Martin Feldmann and is said to be semi-autobiographic.
Werner is depicted as a Motorcycle fanatic in an epic struggle with the authorities regarding the illegal modifications he makes to his bikes. Werner also often takes to a bottle of his favourite beer from a local micro brewery, and the resulting hangovers regularly get him into trouble with his employer, who has a small plumbing business.
The comics are set in and around the city of Kiel in Schleswig-Holstein and they are written in the dialect of the area. They became extremely popular in Germany in the 80s, so much so, that the entire country started to imitate the Schleswig-Holstein dialect for a while.
A lot of Werner's expressions made it into German vernacular.
Both motorcycles the kits depict do exist in real life. The Red XXXXXXX Killer is really called "Red Porsche Killer" and was built for a race between Martin Feldmann and the owner of Martin's favourite pub, who had a red Porsche 911. Porsche did not allow Revell to use its name for the model, despite the Porsche actually won the race.