Namura NX-10026K Top End Kit for 1986-1991 Honda CR250R, 66.34 mm Standard Bore, 8.5:1 Compression

The Namura NX-10026K Top End Kit is designed for Honda CR250R models from 1986 through 1991 equipped with a Nikasil cylinder. This standard-bore replacement kit includes a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit for a complete top-end service. The kit uses a 66.34 mm piston size and is engineered for an 8.5:1 compression ratio, providing a reliable replacement solution for rebuilding the upper portion of the engine.

The piston features MOS2, or Teflon and molybdenum, coated skirts applied through a rolled-on process. This coating is designed to provide a strong bond while reducing friction, improving heat transfer, and helping minimize the possibility of cold seizures. Machined smooth heads help reflect combustion heat and reduce carbon buildup, supporting piston protection and consistent engine operation. The anodized dome improves heat resistance and durability, while the hypereutectic casting process adds silicon for reduced expansion, increased wear resistance, and improved performance under elevated cylinder temperatures.

Fitment includes the 1986, 1987, 1988, 1989, 1990, and 1991 Honda CR250R. Verify the motorcycle year, cylinder type, bore specification, compression ratio, and existing engine components before installation. Manufactured by Namura and identified by manufacturer and vendor part number NX-10026K, this top-end kit is intended for replacement or engine rebuilding applications where dependable fit and durable piston construction are required.

Features:

• Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
• MOS2-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 resistance to high cylinder temperatures
• 66.34 mm standard-bore piston designed for an 8.5:1 compression ratio
• Fits 1986-1991 Honda CR250R models with Nikasil cylinders
• Brand: Namura
• Manufacturer and vendor part number: NX-10026K