REMOVE THE GREASE
Most bearings come packed with grease to lubricate them, and the thickness of the grease slows down the bearings. Spray out the grease using some motor spray and a bearing-cleaner tool, like the one offered by RPM. Roll the bearing to move around any remaining grease, and give them another round of cleaning. Let the bearings dry for a few minutes, then apply a few drops of thin oil (which is available from companies like Dynamite) in various spots on the bearing’s shield and let it soak in.
Clean out the grease in your bearings using some motor spray and a tool like this Bearing Blaster from RPM.
Two drops of oil are all you need in your bearings.