Yamaha Water Return Pipe 2 YF1-68517-33-50. Overview. The Yamaha YF1-68517-33-50 Water Return Pipe 2 is a genuine original equipment manufacturer component designed to help direct coolant or water flow within the engine cooling system. This pipe plays an important role in returning water through the cooling circuit, helping maintain proper circulation and temperature regulation during engine operation.. Efficient coolant movement is essential for preventing overheating and ensuring consistent en