The trouble with anything from 84 is finding stock parts. I would imagine finding many aftermarket parts would be doubly difficult.
I bought my 84 cr500 for cheap money 12 years ago. Took another couple hundred to get it up to decent working order. Then I had to rebuild the shock because after close to 20 (for you it's close to 30) years of bouncing up and down the shock innards were worn. there went another 100$ or more, I forget.
My goal isn't to keep you from getting this bike, or from undertaking this project. I just want you to go into it with your eyes open.
They say you shouldn't look a gift horse in the mouth. I call BS on that. Look in it's mouth, check it's conformation, etc.
To answer your question, I wouldn't know where to find an aftermarket stator that would fit an 84 CR500. You may have to learn how to rewind the one that is there to give you the extra juice you are going to need if you put on lights.