Restore top-end performance on your 2001 Yamaha YZ125 with the Namura NX-40000-BK1 Top End Kit. Designed for reliable fitment with the Yamaha YZ125, this kit includes the essential components needed for a piston replacement, including the piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit. The kit is designed for a 53.95 mm bore and 11:1 compression ratio, making it a practical replacement solution for maintenance, rebuilding, or performance-focused engine service.
The Namura piston features MOS2, a Teflon and molybdenum coating applied to the skirt using a rolled-on process. This method creates a strong bond while helping reduce friction, improve heat transfer, and minimize the risk of cold seizures. The machined smooth head reflects combustion heat and helps reduce carbon buildup, supporting piston protection and consistent engine operation. An anodized dome adds heat resistance and durability, while the hypereutectic casting process provides increased silicon content for controlled expansion and improved wear resistance under elevated cylinder temperatures.
Built for dependable service in the Yamaha YZ125 platform, the Namura NX-40000-BK1 Top End Kit provides a complete set of matched top-end components in one package. Confirm model year, engine configuration, and bore requirements before installation to ensure proper fitment. Manufacturer part number: NX-40000-BK1. Vendor part number: 185-40001B.
Features:
- Fitment: Designed for the 2001 Yamaha YZ125
- Complete top-end kit: Includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- Piston bore: 53.95 mm with an 11:1 compression ratio
- MOS2-coated skirt: Helps reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined smooth head: Reflects combustion heat and helps reduce carbon buildup
- Anodized dome: Improves heat resistance and piston durability
- Hypereutectic casting: Provides controlled expansion and enhanced wear resistance
- Brand: Namura
- Manufacturer part number: NX-40000-BK1
- Vendor part number: 185-40001B
Fitment:
2001 Yamaha YZ125