John, if they are 1/4"" bearings Harley ones will do as you can get the interference fit with the oversized, I'll chuck a few in with the stuff to come back to you if they are
Dave
The screw in type are 3/8" Whit (UNC will do). I think the dowel type are the same size. Just cut them from the un-threaded shank of 3/8" bolts and glue them in with Loctite or similar. Ron
The Magneto base studs (press in) are 5/16" diameter. The threaded ones are 3/8" Whitworth into the mag case reduced to 5/16" at the other end to fit the mag platform slots in the crankcase....Ian