Namura NA-40004-6K Top End Kit, 101.47 mm, 9.2:1 Compression for Yamaha YFM660R Raptor

Restore top-end performance with the Namura NA-40004-6K Top End Kit for Yamaha YFM660R Raptor models. Designed for a 101.47 mm piston size and 9.2:1 compression ratio, this kit provides the essential components needed for a dependable piston replacement and cylinder refresh. It fits 2001 through 2005 Yamaha YFM660R Raptor applications.

The kit includes a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit for a complete top-end installation. The hypereutectic casting process adds silicon to help reduce expansion, improve wear resistance, and withstand higher cylinder temperatures. A machined smooth head helps reflect combustion heat and reduce carbon buildup, while the anodized dome improves heat resistance and piston durability.

Namura also applies a MOS2 Teflon and molybdenum coating to the piston skirts using a rolled-on process that creates a strong bond. This coating helps reduce friction, improve heat transfer, and minimize the risk of cold seizures during operation. Verify engine specifications and piston requirements before installation to ensure compatibility with your cylinder and intended application.

Features:

• Complete top-end kit includes piston, rings, wrist pin, clips, top-end bearing, and gasket kit
• 101.47 mm piston size with a 9.2:1 compression ratio
• MOS2 Teflon and 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 piston dome improves heat resistance and durability
• Hypereutectic casting process provides reduced expansion, increased wear resistance, and improved high-temperature performance
• Fits 2001-2005 Yamaha YFM660R Raptor models
• Brand: Namura
• Manufacturer part number: NA-40004-6K
• Vendor part number: 186-40046