This guy obviously owes money on the bike, that he probably purchased and couldn't finish paying off. There is then a lien on the bike, the bike belongs to the lien holder not to the poor sucker that buys it off of him for parts. They are then in possession of stolen goods, which is a crime... They might not be aware of this because they believe what ever this idiot is saying. Its not just "the man" who might get screwed over here, it could be some unsuspecting buyer who doesn't know the full details.
If we are talking Karma I would have to side with protecting a potential victim and bringing justice to someone who is trying to scam others for their own benefit.
"I've been to jail.... Snitches deserve to die in ditches" this made me laugh pretty hard. You could live by this motto or you could just be a contributing member of society that helps others.
On a side note, I have absolutely no problem with sticking it to "the man". If say Comcast, the most evil company in the world, sent me a check for $2,000 today on accident I would gladly cash it and not say shit about it.