Wow, okay dude.
Let's review the situation here: You had a motorcycle stolen from you 20 years ago, and now based on a picture you saw on Craig's List, you're ready tp go take the bike. You have no idea where the current owner got it, or if the bike is even yours. You then asked for advice on an internet forum, and completely disregarded advice I gave you about legally getting the bike back (IF IT IS YOURS).
Let's say you go look at the bike and the VIN is scratched out. Then what? Are you suggesting that your bike was the only one of this particular model that was ever stolen? Have a little common sense. Doing anything the "illegal way" is a good way to spend a night in jail and still not have the bike. If you want to go off on a half-cocked plan to steal a motorcycle worth approximately $300, then by all means do so. Let us know how it goes for you.