What was found
DURING CLIMB, NR 2 ENG VIB BEGAN INCREASING WITH NOTICEABLE AIRFRAME VIBRATION. AT FULL PWR, VIB INCREASED PAST 4. REDUCED PWR PER QRH TO MAINTAIN 4. PRIOR TO TURNBACK COULD MAINTAIN ONLY 92 PERCENT N1 WITH 4.0 VIB. REMOVED NR 2 ENG FAN BLADES, CHECKED BLADE WEIGHT. TRIM WEIGHT ARE IN CORRECT POSITION, ALL FOUND OK. REINSTALLED FAN BLADE SET PER MM. PERFORMED FAN TRIM BALANCE PER MM AND ADJUSTED WEIGHTS PER AVM.