The swingarm bearings are the same type, caged needles. There are no seals. They are very low speed bearings and they rely on the grease pack to repel water and shielding by the frame to limit water. Since the bearings are at each end of a tube, unsealed and low speed, you can put a grease fitting in the center of the tube and use a grease gun to force grease from the inside of the bearings out to the outside. It will take a lot of grease as the entire tube must be filled and there is a bit of a mess created as the excess leaves the swingarm ends, but the bearings will last practically forever if greased regularly. Grease fittings can be used with needle bearings only if placed between them, not on them.