As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN)WHILE ATTEMPTING TO TRACK AND BALANCE ROTOR ASSEMBLY AFTER A HEAD CHANGE, THE VERTICAL VIBRATION COULD NOT BE REMOVED. DETAILED INVESTIGATION FOUND THE STATIC STOP SHIMMING WAS INCORRECT, THIS ALLOWEDTHE INBOARD FITTINGS TO MOVE WITHIN THE YOKE ASSEMBLY (0.030" SHIM HAD TO BE REMOVED).