Namura NA-10003-4 Piston Kit 1.00mm oversize (85.97mm) high-compression piston kit

The Namura NA-10003-4 Piston Kit is a 1.00mm oversize (85.97mm) high-compression piston kit designed primarily for Honda 400cc engines. It features an 11.0:1 compression ratio, which is higher than the standard stock ratio.

Vehicle Compatibility

This kit is compatible with the following Honda models and year ranges:

• TRX400EX Sportrax: 1999–2008

• TRX400X: 2009, 2012–2014

• XR400R: 1996–2004

Key Specifications & Features

• Bore Size: 85.97mm (+1.00mm / .040" over stock)

• Compression Ratio: 11.0:1 High Compression

• Skirt Coating: MOS2 (Teflon/Molybdenum) coated to reduce friction and prevent cold seizures.

• Anodized Dome: Increases heat resistance and durability.

• Kit Contents: Piston, a set of OEM-quality rings, a wrist pin, and circlips.

Important Note: This piston and its rings are not interchangeable with OEM components. You must use Namura-specific rings for this piston, and the cylinder must be bored to 86.00mm to accommodate the 1.00mm oversize.

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