All things final drive.

The gearbox cush drive.

The first picture shows a doughnut rubber breaking up. The wire mesh can be seen at the centre boss. If this fails the bike becomes almost immoveable. Picture 2 shows a worn cushdrive doughnut. The centre bosses are starting to break away.
Picture 2 shows cushdrive components and picture 3 shows part assembly. Picture 4 shows completed and painted ready to reinstall.