What are the signs of excessive sprocket wear on a motorcycle final drive system that require immediate replacement of both sprockets and chain?

1. Sprocket teeth become perfectly rounded and mirror-polished on all sides
2. The rear sprocket changes its tooth count automatically during gear changes
3. Sprocket teeth become asymmetrical, thinned, pointed, or hook-shaped ('shark-tooth' profile)
4. The sprocket begins emitting high-frequency ultrasonic radio signals