I thought that it was best to just let him use a can spray paint rather than a real paint gun. I really don't want him spraying paint all over the place.
He didn't do much preparation before painting. He just brushed the frame and used Scotch Brite cleaning pads. Covered the engine and swing arm with newspaper and off he painted. No primers nor bogs, I just let him spray it the way he wanted to.
The wind was quite strong that day and got some paint on four of my other motorcycles including the Kawasaki ZZR on the background. It took me days polishing the other four bikes to remove the black paint but since I was the one who was too lazy to move them, I really couldn't put the blame on anybody.
He did about five coatings. Two coats or three are enough but he seemed to be having a good time so I just let him enjoy his project.