Also known as the the Baader-Meinhof gang, the leftists killed Buback and two others when an unidentified gunman fired a spray of bullets at his chauffeured car on April 7 that year.
“The motorcycle in question is evidently the motorcycle used in the crime,” a spokesperson for the federal prosecutor's office in Karlsruhe said on Monday.
The find comes in the midst of a trial against former RAF member Verena Becker, who is accused of playing a role in the political assassination. She is not suspected of pulling the trigger, though Buback's son has said he is convinced the 58-year-old was the shooter.
Other members of the group have already been convicted for the killing, but the actual murderer has never been identified.
Whether investigators will be able to find any DNA traces on the vehicle remains unclear, the spokesperson said.
“It's being clarified as to whether today's forensic methods can even secure traces relevant to the crime,” he said.
Police did initially secure the motorcycle, a 1977 Suzuki GS 750, shortly after the shooting. But after they completed their investigation, the vehicle was sold “because it was no longer needed as evidence.”
According to daily Pforzheimer Zeitung on Saturday, the vehicle was purchased in 1982 at a discounted price by a man in Böblingen county, who found it listed in a local paper.
The man has apparently not driven the motorcycle for the last 10 years.
Last week at Becker's trial, a federal police investigator said that important court exhibits from the Buback murder trial – namely the motorcycle and the getaway car - had gone missing.
The Baader-Meinhof gang, named after its founders Andreas Baader and Ulrike Meinhof, attacked Buback in one of several RAF crimes staged in protest of what they saw as the oppressive West German state. The bloody era came to be known as the “German Autumn.”