As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER COMPLETING A 100 HOUR AND BALANCING THE TAIL ROTOR A VIBRATION WAS FELT THROUGH THE PEDALS. FURTHER TROUBLESHOOTING REVEALED THE DISK ASSEMBLY WAS NOT AS STIFF AS ON OTHER AIRCRAFT. DISK ASSEMBLY CHANGED, VIBRATION DISAPPEARED.