Namura NX-10003K1 Top End Kit 53.94 mm Standard Bore, 11:1 Compression for Honda CR125R

The Namura NX-10003K1 Top End Kit is designed for select Honda CR125R two-stroke motorcycles from 2005 through 2007. This standard-bore kit includes a 53.94 mm piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit, providing the essential components for a reliable top-end rebuild. It is engineered to restore performance and support proper fitment with the original cylinder.

The piston uses a hypereutectic casting process that increases silicon content to help control 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.

Machined smooth heads help reflect combustion heat and reduce carbon buildup around the piston crown, while the anodized dome improves heat resistance and durability. The 11:1 compression ratio is matched to the listed application, supporting dependable engine operation when installed with the appropriate cylinder, components, and manufacturer specifications. The Namura NX-10003K1 is a practical replacement top-end solution for maintaining the performance and serviceability of compatible Honda CR125R models.

Fitment: Fits 2005 Honda CR125R, 2006 Honda CR125R, and 2007 Honda CR125R. Manufacturer part number: NX-10003K1. Vendor part number: 185-10031.

Features:

• Complete Top End Kit: Includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
• Standard Bore Fitment: Features a 53.94 mm piston designed for compatible Honda CR125R applications
• MOS2-Coated Skirts: Teflon/Molybdenum coating helps reduce friction, improve heat transfer, and minimize cold-seizure risk
• Machined Smooth Head: Helps reflect combustion heat and reduce carbon buildup on the piston crown
• Anodized Dome: Improves heat resistance and durability for demanding engine conditions
• Hypereutectic Construction: Higher silicon content helps reduce expansion, increase wear resistance, and withstand higher cylinder temperatures
• 11:1 Compression Ratio: Designed to support the specified Honda CR125R engine configuration
• Fitment: Compatible with 2005–2007 Honda CR125R models