Without a vin # how do you register or get insurance on the bike. I would think that would be your first priority before getting it to run. As far as your original question goes I'm not sure if you can use the same coil for both engines. I do know that there where changes to the J series(00-01) motor which increased horse power to 112. if you google the two bikes and ask if the parts can be swapped you get a guy called (ttr50rider12) on the kawiforums that says the coils cannot be swapped. After reading his statement it would appear that he has done quite abit of research on this topic and gives a whole list of what parts can be swapped and what parts can't and why. Hope this helps.