I was pleasantly surprised when the mechanic found the source of a vibration with a visual inspection of my front wheel bearings. There was no problem with the bearings but I previously cut the cotter pin for the castellated nut too long and the edge of the cotter pin was rubbing on the inside of the hub dust cap causing the problem. A new cotter pin and the symptoms were eliminated. Sometimes there is just no substitution for experience. Thanks for fixing me up!