Upgrade the top end of your 2001 Yamaha YZ125 with the NAMURA NX-40000-CK1 Top End Kit. Designed for dependable replacement performance, this kit includes a piston, piston rings, wrist pin, circlips, top-end bearing, and gasket kit. The ceramic compression piston is engineered for a 53.96 mm bore application with an 11:1 compression ratio, providing a complete solution for refreshing the engine’s upper cylinder assembly.
The NAMURA piston uses a hypereutectic casting process that increases silicon content to help reduce expansion, improve wear resistance, and withstand elevated cylinder temperatures. Its MOS2, or Teflon/molybdenum, coated skirts use a rolled-on application process intended to create a stronger bond than conventional spray-on coatings. This coating helps reduce friction, improve heat transfer, and minimize the risk of cold seizures during operation.
Additional piston features include a machined smooth head that helps reflect combustion heat and reduce carbon buildup, along with an anodized dome designed to improve heat resistance and durability. NAMURA states that anodized domes provide substantially greater strength than non-anodized designs. The included gasket kit, wrist pin, circlips, rings, and top-end bearing help simplify installation when servicing the cylinder and piston assembly.
Fitment: This NAMURA top-end kit fits the 2001 Yamaha YZ125. Verify the motorcycle model year, cylinder bore, piston specification, and engine configuration before installation. Manufacturer part number: NX-40000-CK1. Vendor part number: 185-40001C.
Features:
- Complete top-end kit includes piston, rings, wrist pin, circlips, top-end bearing, and gasket kit
- 53.96 mm ceramic compression piston designed for an 11:1 compression ratio
- MOS2 Teflon/molybdenum-coated 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 dome improves heat resistance and piston durability
- Hypereutectic casting process provides reduced expansion, added wear resistance, and improved high-temperature capability
- Fitment: 2001 Yamaha YZ125
- Brand: NAMURA
- Manufacturer part number: NX-40000-CK1
- Vendor part number: 185-40001C
Fitment:
2001 Yamaha YZ125