Yamaha Crankshaft & Oil Pump Set 99999-04012-00. Overview. The Yamaha Crankshaft & Oil Pump Set 99999-04012-00 is a genuine original equipment manufacturer assembly designed to support efficient engine lubrication and reliable crankshaft operation. This essential set ensures consistent oil flow throughout the engine, helping reduce friction, control heat, and protect critical internal components from premature wear.. Maintaining proper oil circulation is key to engine performance and longevity.