Yamaha - Fuel Pump Gasket Fuel System Sealing Component YF1-62645-21-40. Overview. When you're working on Yamaha fuel systems, it's usually the small sealing parts that end up causing the biggest issues. I've seen engines struggle with fuel delivery just because of a worn gasket letting air or fuel leak where it shouldn't. The Yamaha Fuel Pump Gasket YF1-62645-21-40 keeps that seal tight so the pump can do its job properly. It's a simple piece, but without it, the whole fuel system can start act