{"product_id":"namura-top-end-kit-81-45-mm-11-1-compression-for-polaris-trail-boss-350l-part-na-50001-6k","title":"Namura Top End Kit 81.45 mm, 11:1 Compression for Polaris Trail Boss 350L, Part NA-50001-6K","description":"\u003cp\u003eRestore dependable top-end performance with the Namura Top End Kit for compatible Polaris Trail Boss 350L models. This kit includes a piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit for a complete refresh of the engine’s upper assembly. The 81.45 mm piston uses an 11:1 compression ratio and is designed for reliable fitment on select 1990–1993 Polaris Trail Boss 350L 2X4 and 4X4 applications.\u003c\/p\u003e\u003cp\u003eThe piston features Namura’s MOS2, or Teflon and molybdenum, coated skirts. This rolled-on coating process creates a strong bond while helping reduce friction, improve heat transfer, and minimize the risk of cold seizure. The machined smooth head helps reflect combustion heat and reduce carbon buildup, supporting piston protection and consistent engine operation. An anodized dome further improves heat resistance and durability compared with a non-anodized piston.\u003c\/p\u003e\u003cp\u003eManufactured using a hypereutectic casting process, the piston contains increased silicon content to help control expansion, improve wear resistance, and withstand higher cylinder temperatures. The kit is intended for engine rebuilding or top-end service where the original piston and related components require replacement. Verify the year, model, drivetrain configuration, bore requirement, and engine specifications before installation.\u003c\/p\u003e\u003cp\u003eManufacturer part number: NA-50001-6K. Vendor part number: 186-50016. Fitment includes the 1990, 1991, 1992, and 1993 Polaris Trail Boss 350L 2X4, plus the 1990, 1991, 1992, and 1993 Polaris Trail Boss 350L 4X4.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eFeatures:\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eComplete top-end kit includes piston, rings, wrist pin, retaining clips, top-end bearing, and gasket kit\u003c\/li\u003e\n\u003cli\u003e81.45 mm piston size with an 11:1 compression ratio\u003c\/li\u003e\n\u003cli\u003eMOS2 Teflon and molybdenum coated skirt helps reduce friction, improve heat transfer, and minimize cold-seizure risk\u003c\/li\u003e\n\u003cli\u003eMachined smooth piston head helps reflect combustion heat and reduce carbon buildup\u003c\/li\u003e\n\u003cli\u003eAnodized dome improves heat resistance and piston durability\u003c\/li\u003e\n\u003cli\u003eHypereutectic casting process provides controlled expansion, increased wear resistance, and improved high-temperature capability\u003c\/li\u003e\n\u003cli\u003eFits 1990–1993 Polaris Trail Boss 350L 2X4 and 4X4 models\u003c\/li\u003e\n\u003cli\u003eBrand: Namura\u003c\/li\u003e\n\u003cli\u003eManufacturer part number: NA-50001-6K\u003c\/li\u003e\n\u003cli\u003eVendor part number: 186-50016\u003c\/li\u003e\n\u003c\/ul\u003e\u003cbr\u003e\nFitment:\u003cbr\u003e\n1990 Polaris Trail Boss 350L 2X4\u003cbr\u003e\n1990 Polaris Trail Boss 350L 4X4\u003cbr\u003e\n1991 Polaris Trail Boss 350L 2X4\u003cbr\u003e\n1991 Polaris Trail Boss 350L 4X4\u003cbr\u003e\n1992 Polaris Trail Boss 350L 2X4\u003cbr\u003e\n1992 Polaris Trail Boss 350L 4X4\u003cbr\u003e\n1993 Polaris Trail Boss 350L 2X4\u003cbr\u003e\n1993 Polaris Trail Boss 350L 4X4","brand":"NAMURA","offers":[{"title":"Default Title","offer_id":67558764937451,"sku":"186-50016","price":128.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0611\/3882\/9547\/files\/dd77-572a583cd9540_2b20fc45-c1e2-4e37-92a5-2055d1682da3.jpg?v=1790768909","url":"https:\/\/ctracingservices.com\/products\/namura-top-end-kit-81-45-mm-11-1-compression-for-polaris-trail-boss-350l-part-na-50001-6k","provider":"Cascade Tire \u0026 Racing Services","version":"1.0","type":"link"}