Yamaha Self-Locking Nut - 90185-14081-00. Engineered Retention for High-Vibration Yamaha Assemblies. The Yamaha - Nut, self-locking - 90185-14081-00 is a factory-original fastener designed to provide secure, vibration-resistant locking for critical Yamaha engine and equipment components. This nut features a self-locking mechanism that prevents loosening over time, even in high-stress or high-rotation assemblies.. If you're conducting repairs or preventative maintenance on your Yamaha engine, usi