Yamaha Thermostat 705-12411-02-00. Overview. The Yamaha Thermostat 705-12411-02-00 is a genuine original equipment manufacturer component designed to regulate engine temperature by controlling coolant flow. This essential part ensures your engine operates within the proper temperature range, helping maintain performance, efficiency, and longevity.. Engineered to Yamaha's exact specifications, this thermostat provides a precise fit and dependable operation. It is an ideal replacement for worn or