KOYO Crankshaft Main Bearings are meticulously crafted to precise OEM standards using the highest quality materials. These bearings are designed to fit perfectly with both OEM and aftermarket crankshafts, ensuring optimal performance and durability. Each KOYO bearing undergoes rigorous testing to meet or exceed the specifications required for reliable and efficient engine operation. Ideal for maintaining the engine's integrity and performance, KOYO bearings provide a seamless fit and long-lasting reliability, making them an excellent choice for Yamaha engines.