Originally Posted by EjustE

Same thing that happens with any stolen property sold (think of someone buying a stolen camera from a pawn shop e.g.) :

the original owner has the burden of proof that the property is indeed his/hers (and he had better filed a police report to report the property as stolen) and the final buyer/current owner has the right of compensation/retribution from the thief (if known/caught), otherwise he/she is SOL, if proven in a court that his current property rightfully belongs to someone else (and this is a civil law case). There are no involvement/issues of the intermediate owners/buyers/sellers etc, unless they knowingly sold stolen property (the burden of proof is on the state on this one and this is a criminal law case). This is how it goes pretty much, with a few variations, mainly on the rights of retribution and how much of the first case is civil vs. criminal and why, depending on the state.

To the OP: let the bike be where it is. Call the cops/sheriff to impound it.