Unfortunately, if you are not the owner of the bike and the bike is not under your name, then there is not much you can do. One question that remains obvious is the circumstances under which you claim ownership of the bike. How is it that you claim to own the bike when there is another owner and your name is not on the title? Did someone sell you the bike? Furthermore, how is it that the police department impounded the bike? Were you or someone else riding the bike while violating traffic laws, for example, were you riding the bike without a helmet? These are all important questions that a lawyer would have to ask to properly answer your question. In the short of it, however, it appears that if you are not the owner and your name is not on the title, there is not much you can do to get it back.