Restore reliable top-end performance with the NAMURA NA-50025K Standard Top End Kit for select Polaris 330 ATV models. This complete kit includes a piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit, providing the essential components needed for a top-end rebuild. The piston is designed with an 11:1 compression ratio and a standard bore application for precise fitment and dependable operation.
NAMURA uses a hypereutectic casting process to increase silicon content, helping reduce thermal expansion and improve wear resistance under demanding cylinder temperatures. The piston skirt features a MOS2 coating made from Teflon and molybdenum. Its rolled-on application creates a strong bond while helping reduce friction, improve heat transfer, and minimize the risk of cold seizures. A machined-smooth head helps reflect combustion heat and reduce carbon buildup, supporting piston protection and consistent engine performance.
The anodized dome improves heat resistance and durability, making this piston suitable for ATV engines exposed to recreational riding and utility use. The NAMURA NA-50025K top-end kit fits 2008–2013 Polaris Trail Blazer 330 models and 2003–2006 Polaris Trail Boss 330 models. Verify the engine model, standard bore requirement, and existing cylinder condition before installation. Manufacturer part number: NA-50025K. Vendor part number: 186-5025.
Features:
- Complete top-end kit includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit
- Standard bore piston with an 11:1 compression ratio and 78.45 mm nominal piston size
- MOS2 Teflon and molybdenum coated skirt helps reduce friction, improve heat transfer, and minimize cold-seizure risk
- Machined-smooth piston head helps reflect combustion heat and reduce carbon buildup
- Anodized dome improves heat resistance and piston durability
- Hypereutectic casting process provides reduced expansion, increased wear resistance, and improved high-temperature performance
- Fits 2008–2013 Polaris Trail Blazer 330 and 2003–2006 Polaris Trail Boss 330 models
- Brand: NAMURA
- Manufacturer part number: NA-50025K
- Vendor part number: 186-5025
Fitment:
2003 Polaris Magnum 330 2X4
2003 Polaris Magnum 330 4X4
2003 Polaris Trail Boss 330
2004 Polaris Atp 330
2004 Polaris Magnum 330 2X4
2004 Polaris Magnum 330 4X4
2004 Polaris Trail Boss 330
2005 Polaris Atp 330
2005 Polaris Magnum 330 2X4
2005 Polaris Magnum 330 4X4
2005 Polaris Trail Boss 330
2006 Polaris Magnum 330 4X4
2006 Polaris Trail Boss 330
2007 Polaris Trail Boss 330
2008 Polaris Trail Blazer 330
2008 Polaris Trail Boss 330
2009 Polaris Trail Blazer 330
2009 Polaris Trail Boss 330
2010 Polaris Trail Blazer 330
2010 Polaris Trail Boss 330
2011 Polaris Trail Blazer 330
2011 Polaris Trail Boss 330
2012 Polaris Trail Blazer 330
2012 Polaris Trail Boss 330
2013 Polaris Trail Blazer 330
2013 Polaris Trail Boss 330