Fritz Klager was first and foremost, a motorcycle racer, but in the 1950s, he built engines and gearboxes for himself and for friends. He was in the top ten German riders several times, and became a factory rider for Horex in the mid 1950s. He finished 2nd in the 350cc championship in 1957. He went on to race Moto GP for Horex, where his best finish was 15th at the French Grand Prix in 1960.
Perhaps it was the many DNFs that were suffered on the Horex, that convinced him to start Fritz Klager Spezials in the mid 1960s. He produced 3 variations, a 250cc twin, a 350cc triple, and a 500cc triple. His last victory before retirement was in 1969 at Schauinsland aboard one of his own machines. FKS ceased building racers in 1970.