Namura NX-40026-CKA Top End Kit for 1995–1998 Yamaha YZ250, 67.96 mm Bore

The Namura NX-40026-CKA Top End Kit is designed for reliable replacement and performance restoration on select 1995–1998 Yamaha YZ250 models. This complete kit includes a piston, piston rings, wrist pin, circlips, top-end bearing, and gasket kit, providing the primary components needed for a professional top-end rebuild. With a 67.96 mm piston size and an 11:1 compression ratio, it is engineered for dependable fitment and consistent operation in compatible Yamaha two-stroke engines.

The piston uses a hypereutectic casting process that increases silicon content to help control expansion, improve wear resistance, and withstand elevated cylinder temperatures. The MOS2, or Teflon/molybdenum, coated skirts use a rolled-on application process designed 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 engine operation.

Machined smooth heads help reflect combustion heat and reduce carbon buildup around the piston crown, supporting piston protection and efficient combustion. Anodized domes further improve heat resistance and durability, making the piston suitable for demanding off-road riding and motocross applications. The Namura NX-40026-CKA top-end kit fits 1995, 1996, 1997, and 1998 Yamaha YZ250 models. Verify the motorcycle year, model, cylinder condition, and required piston clearance before installation.

Features:

• Complete top-end kit includes piston, rings, wrist pin, circlips, top-end bearing, and gasket kit
• 67.96 mm piston size with an 11:1 compression ratio for compatible Yamaha YZ250 applications
• MOS2 Teflon/molybdenum coated piston skirts help reduce friction, improve heat transfer, and minimize cold-seizure risk
• Machined smooth piston heads help reflect combustion heat and reduce carbon buildup
• Anodized piston domes improve heat resistance and durability
• Hypereutectic casting process provides controlled expansion, increased wear resistance, and improved high-temperature performance
• Fits 1995–1998 Yamaha YZ250 motorcycles
• Brand: Namura
• Manufacturer part number: NX-40026-CKA
• Vendor part number: 185-4026CA