I was determined to do my conversion by myself. So, I mounted the flywheel in a work bench type drill press(with a drill). Put a bolt through the flywheel and glued sandpaper to a piece of wood and monted that on the bottom of the press. Chucked it in the drill and started sanding away. Not the fastest way to do it but it worked. I did not balance it and still have yet to fire it up on the test stand. So hopfully it is not way out of balance.
Here is a pic.

Bill