Namura NX-40000K Standard 53.94 mm Top End Kit for 1998–2000 Yamaha YZ125

Restore top-end performance and dependable engine operation with the Namura NX-40000K Standard Top End Kit for select Yamaha YZ125 models. Designed for a standard 53.94 mm bore and an 11:1 compression ratio, this complete kit includes the essential components needed for a thorough top-end rebuild: piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit.

The Namura piston uses a hypereutectic casting process that increases silicon content to help reduce expansion, improve wear resistance, and withstand higher cylinder temperatures. Its MOS2, or Teflon/molybdenum, coated skirts are applied using a rolled-on process that creates a strong bond while helping reduce friction, improve heat transfer, and minimize the risk of cold seizures. The machined-smooth head helps reflect combustion heat and reduce carbon buildup, while the anodized dome increases heat resistance and durability.

Fitment: This Namura NX-40000K top-end kit fits 1998 Yamaha YZ125, 1999 Yamaha YZ125, and 2000 Yamaha YZ125 applications. Confirm the existing cylinder bore, compression requirements, and engine configuration before installation to ensure proper compatibility. Manufactured by Namura and identified by manufacturer part number NX-40000K, this kit provides a convenient solution for replacing worn top-end components during engine maintenance or performance restoration.

Features:

• Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
• Standard 53.94 mm piston size with an 11:1 compression ratio
• MOS2 Teflon/molybdenum coated piston skirts help reduce friction, improve heat transfer, and minimize cold-seizure risk
• Machined-smooth piston head helps reflect combustion heat and reduce carbon buildup
• Anodized piston dome improves heat resistance and durability
• Hypereutectic casting process provides reduced expansion, increased wear resistance, and improved high-temperature durability
• Fits 1998–2000 Yamaha YZ125 models
• Brand: Namura; manufacturer and vendor part number: NX-40000K