WD40 leaves a lubricating residue that is not made to withstand the speed at which the bearing spins. I don’t use it and recommend you use a solvent (acetone, naptha, mineral spirits) to get it off prior to oiling. It will cause friction on it’s own, you need to put oil on afterward anyway if you choose not to rinse it off. Would do better to use lighter fluid, or paint thinner if availible.