If the starter is whining while the engine is running at an idle you have a problem with the ignition switch or the starter solenoid is stuck. The starter should not be engaged while the engine is running unless you are holding the key over on the start position.
A small flywheel needs to stay with the starter that goes to it. You can use either flywheel, and the block should be drilled for either starter.
if the starter is spinning but not engaging then the bendix (starter teeth) is not moving out to grab the flywheel teeth or the flywheel has some broken teeth. The starter needs to be removed to see what the issue is.
Whines? If its not a grinding scritching noise more common then just a whine, if it is indeed a whine I would tend to think that your starter's drive roller clutch is worn to the point that the drive will need replacing, they are about $10=20. likely time for a starter overhaul, Bushings, brushes, Solenoid.
The starter is probably not aligned with the flywheel. The clearance between the starter and the ring gear needs to be checked.
The answer to the question is no. If the flywheel is ground or damaged it needs to be replaced.
the stater motor needs replacing it is not the solenoid that does not kick out it is the gear on the shaft sticking in the flywheel so either the starter is worn, the gear on starter is worn, or the teeth on the flywheel are worn if you replace stater, make sure correct number of teeth on gear or you will just mess up another one
Remove the starter and have it bench tested at your local auto parts store.
Yes, if the drive gears are going too far in toward the flywheel because a shim is missing, you will damage either the starter gears, flywheel, or both.
Sounds like starter solenoid is going bad and needs replacing
It can be the starter bendix is not engaging the starter gear into the flywheel. It can also be a broken tooth on the flywheel itself. Try pushing the bike and then releasing the clutch. This will turn the engine over just enough to move the flywheel. If it then engages and starts, suspect you have a broken tooth. If that is not the case, then remove the starter and test it by applying 12 volts and see it the bendix kicks the gear out.
possible that it was inproperly installed or needs replacing and it could be the clutch to so open er up.
if you mean can a novice replace the starter, the answer is yes. any other repairs to starter just depend on what needs replacing