Did it ever have a street legal title? If not it's a huge pain in the ass. I started the process a few years ago with a Sand Rail but gave up and sold it.
I have plated a few dirt bikes and those are pretty easy AS LONG AS THEY WERE NEVER TITLED.
If it was titled at one time you'll have to go through the bonded title process which isn't terrible but it will cost some money and a decent amount of leg work/time.