All Balls Rear Carrier Bearing Upgrade Kit O.E.M. Carrier YAMAHA YFZ 450 Bearings typically fail from water and dirt contamination. The All Balls Rear Carrier Bearing and Seal Kits were developed and designed for the difficult operating environment of the powersports industry. Kits contain ball bearings and seals - all that is required to successfully upgrade a rear carrier for smoother operation.