When you register the motorcycle just say "That is private." when they inquire about the price.

If you avoid getting the plates it is likely you will get silence and acquiescence to your process. Great! But that default will not stop a prosecution, especially if you have to sign a bail bond agreement to get your process into the case.

The right to contract is sacrosanct to peaceful civil authority in America. This is why I am simply assuring myself at every opportunity that the officers pretending to be judicial are properly bonded by their own signature bond - oath of office.