Well, you might be screwed if you can't track this guy down. What isn't clear is if the bike is financed through credit card-type financing or through a bank. You can contact the DMV to find out if there's a lien on the title. You might luck out. If there's no lien, you can apply for a lost title.
If there's a lien on the bike, then what you need to do is let the bank or creditor do the legwork and track the guy down. This might work in your favor, as you could offer to "buy" the bike from the bank for an unreasonably low price. Take the fairings off first and tell them you bought it as is

Otherwise, you are not responsible for the balance due on the bike, but you are basically out the cash you paid the guy and the bank will take the bike.
But don't pay any attention to the lame advice I've given above. Since this is several thousand dollars we're talking about here, your best bet is to contact a LAWYER and file a civil claim.
"At no point in your rambling, incoherent response were you even close to anything that could be considered a rational thought. Everyone in this room is now dumber for having listened to it. I award you no points, and may God have mercy on your soul."