You might search flea bay and on-line
try this search
kawasaki fc540 engine flywheel
Shipping might be a problem, but vs cost of another machine.
Seen some flywheels with free sipping and some with $9 shipping. (don't sound right so beware)
Buy with caution from flea bay.
If you do not see anything, try a saved search, so as to get a email later if one surfaces.
Keep in mind when a magnet breaks it has two OPPOSITE POLARITY poles again, so gluing them back together for a flywheel stator would have a cancelling effect for magnetic field to the stator winding. similar to peeing into the wind.