HM-4G3-Z-16: Main Gear for Walkera 4G3, V120D03 & Heli-Max Novus CP

Improperly installed main gear will prematurely damage your main gear.  The main gear is made of wear resistant PVC but it's still not as hard as the brass pinion on the main motor.  Although, moderate gear mis-alignment may not be apparent at first because the helicopter will still function normally.  But, over time, a mis-aligned gear will wear unevenly causing the main gear to bind.  So after you have installed/replaced the main gear, make sure the gear can rotate manually, evenly and freely.  Any horizontal mis-alignment can be adjusted by nudging the main motor and thus the pinion toward or away from the main gear.  Any vertical mis-alignment can be adjusted by pushing or pulling the pinion up or down the main motor shaft.