Motocross Swing ARM Maintenance Parts Thrust Needle Roller Bearing Oil Seal Bushing For WR250F WR4500F YZ250 This assembly includes a thrust needle roller bearing, oil seal, and bushing designed for use in the swing arm of select motocross motorcycles.The components are engineered to support rotational movement and maintain proper lubrication within the swing arm pivot system.Suitable for models including WR250F, WR450F, and YZ250, these parts assist in smooth suspension and drivetrain alignment.Each is built to meet specifications for fit and function.