How do you get a VIN for a homemade motorcycle or mini chopper?

most state require you to get it inspected and they will give you a plate.

It will vary from state to state. Try contacting your state DMV or a local motorcycle shop may be able to provide you with information.

In Pennsylvania, there is a set of forms required to be submitted to the state, MV426B. The bike must be inspected by a inspection mechanic, photos of the bike must be submitted, a list of materials used and their sources will need to be listed, and all paperwork must be sent in.

Every state surely is different.