To Russia Without Love - S6-E18
Revealing mistake: As the motorcycle and the side car split apart and drive around independently, you can see that the side car has been given two extra wheels, and some other stuff underneath as well that's not present on regular Wehrmacht BMW sidecars - probably a remote control of sorts. Also, the motorcycle Schultz rides has training wheels mounted in the shot where the side car comes off.
Answer: It's a comedy, not a documentary.
stiiggy
Perhaps it was counterfeit. There are numerous episodes where they deal in counterfeit monies.