I made the first ball bearing advance I ever saw, Loctited to the crank and connected to the carb with links, SEVENTEEN years ago, still doing it on the larger engines..I found out early on that the Loctite sometimes fails..All subsequent hubs have the ball bearing mounted on the HUB on a short extension, .669 diameter for a light press fit with Loctite...Tried the 2 sensor setup, decided it was not needed on smaller engines...Or ANY type of advance/retard at all.....
If you're timing an ignition, measure the diameter of the hub that the magnet is mounted in, multiply by .244 for 28 degrees..Works with any size...
Diameter x 3.14, divided by 360, x 28....Works out to .244...
2" x 3.124 = 6.28
divided by 360 for 1 degree = .0174444.. X 28 = .48832
Not at all critical, a few degrees one way or the other makes no measureable difference..
If you go too far on the advance the engine will miss and cut out at WOT, not far enough and the engines slows down and loses power..Best setting is JUST above the point where the engine starts to slow down...