Yamaha Idle Gear Component YF1-58752-40-15. Overview. The Yamaha YF1-58752-40-15 Idle Gear Component is a genuine original equipment manufacturer part designed to support smooth mechanical operation within the engine system. This gear plays a key role in transferring rotational motion between engine components, helping maintain proper timing and efficient power transmission.. Precision engineered to Yamaha specifications, the idle gear component helps ensure reliable performance and proper align