Yamaha - Gear Pump Assembly Oil Injection Component 6D8-43830-01-00. Overview. This gear pump assembly is one of those parts you rely on without thinking about it-until oil delivery becomes a problem. It's responsible for keeping a steady flow of oil moving through the system, which is critical for protecting internal engine components under load. When it's doing its job, everything runs smooth and quiet, even on long runs. When it starts to wear out, you'll notice changes quick, and it's not so