As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED A VERTICAL VIBRATION. INSPECTION REVEALED THE BOLT WHICH ATTACHES THE MAIN ROTOR PITCH LINK UPPER ROD END TO THE MAIN ROTOR HEAD PITCH LEVER ASSEMBLY WAS SEVERELY WORN. FURTHER INSPECTION REVEALED THE LEVER ASSEMBLY BUSHINGS WERE ALSO WORN FROM THE BOLT MOVEMENT.