So I've been planning on building my own motorized bikes. I'm gonna get a 49cc 4 stroke HuaSheng, so that's within the legal limits of NJ of what I've read so far. The only issue I think I could encounter is the fact that it says it wants paperwork of either the purchase or from the previous owner. What's the laws behind that if I'm just throwing on a motor onto a bike? Do I provide some proof of purchase for just the motor? Also It said it needed proof of insurance, which I couldn't imagine being able to get without some form of registration number for my bike! If someone went through this process let me know what to expect, and whether it's a complicated process or not. Thanks! Keblic Update: I called NJDMV and it seemed like nobody actually knew the process to get a custom built motorized bike titled. I just kept getting transferred to different departments until I finally ran into someone who knew a little bit about it. They're sending me a 20 or so page packet about custom built vehicles and how to get them registered... Hopefully when that comes I'll get some much needed information. After this whole process is over I'll make a nice post about what to do and my experience registering the build in NJ.