Yamaha - Gear,balance 3 - YF1-49212-64-62Yamaha Balance Gear Engine Balance System YF1 49212 64 62 Overview Balance gears are one of those parts you dont think about until the engine starts feeling rough or noisy. Ive seen Yamahas come in with vibration issues that traced back to worn or misaligned balance components. The Yamaha Balance Gear YF1 49212 64 62 helps keep engine rotation smooth by countering internal movement. When its doing its job, the engine runs quieter and feels a lot more