Yamaha Gear 1 6X0-48121-00-00. Overview. The Yamaha Gear 1 6X0-48121-00-00 is a genuine original equipment manufacturer component designed to ensure smooth and efficient mechanical operation within your Yamaha system. This gear plays a key role in transferring motion and maintaining proper timing, supporting consistent and reliable performance.. Engineered to Yamaha's exact specifications, this gear provides a precise fit and dependable durability. It is an ideal replacement for worn or damaged