{"product_id":"namura-na-50000-6k-top-end-kit-73-46-mm-1-50-mm-11-1-compression-for-polaris-250","title":"Namura NA-50000-6K Top End Kit, 73.46 mm \/ +1.50 mm, 11:1 Compression for Polaris 250","description":"\u003cp\u003eThe Namura NA-50000-6K Top End Kit is a complete replacement solution for select Polaris 250 engines. This kit includes a piston, piston rings, wrist pin, wrist-pin clips, top-end bearing, and gasket kit for a convenient engine rebuild. Designed with a 73.46 mm \/ +1.50 mm piston size and an 11:1 compression ratio, it supports reliable performance and proper fitment for compatible Polaris applications.\u003c\/p\u003e\u003cp\u003eThe piston features MOS2, or Teflon\/Molybdenum, coated skirts applied through a rolled-on process. This coating provides a strong bond while helping improve heat transfer, reduce friction, and minimize the risk of cold seizures. The machined smooth head reflects combustion heat and helps reduce carbon buildup, protecting the piston crown during operation. An anodized dome further improves heat resistance and durability, while the hypereutectic casting process adds silicon for reduced expansion, increased wear resistance, and improved performance under elevated cylinder temperatures.\u003c\/p\u003e\u003cp\u003eFitment includes the 1991-1992 Polaris Big Boss 250 6X6, 1989-1992 Polaris Big Boss 250 4X6, 1992-1993 and 2003-2004 Polaris Trail Blazer 250. Verify the vehicle year, model, engine configuration, and required oversize before installation. This Namura top-end kit is manufactured for dependable replacement performance and is identified by manufacturer and vendor part number NA-50000-6K.\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, clips, top-end bearing, and gasket kit\u003c\/li\u003e\n\u003cli\u003e73.46 mm \/ +1.50 mm piston size with an 11:1 compression ratio\u003c\/li\u003e\n\u003cli\u003eMOS2 Teflon\/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 increases heat resistance and piston durability\u003c\/li\u003e\n\u003cli\u003eHypereutectic casting process provides reduced expansion, improved wear resistance, and greater tolerance of high cylinder temperatures\u003c\/li\u003e\n\u003cli\u003eFits 1989-1992 Polaris Big Boss 250 4X6 models\u003c\/li\u003e\n\u003cli\u003eFits 1991-1992 Polaris Big Boss 250 6X6 models\u003c\/li\u003e\n\u003cli\u003eFits 1992-1993 and 2003-2004 Polaris Trail Blazer 250 models\u003c\/li\u003e\n\u003cli\u003eBrand: Namura\u003c\/li\u003e\n\u003cli\u003eManufacturer and vendor part number: NA-50000-6K\u003c\/li\u003e\n\u003c\/ul\u003e\u003cbr\u003e\nFitment:\u003cbr\u003e\n1989 Polaris Big Boss 250 4X6\u003cbr\u003e\n1990 Polaris Big Boss 250 4X6\u003cbr\u003e\n1990 Polaris Trail Blazer 250\u003cbr\u003e\n1991 Polaris Big Boss 250 4X6\u003cbr\u003e\n1991 Polaris Big Boss 250 6X6\u003cbr\u003e\n1991 Polaris Trail Blazer 250\u003cbr\u003e\n1991 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1992 Polaris Big Boss 250 4X6\u003cbr\u003e\n1992 Polaris Big Boss 250 6X6\u003cbr\u003e\n1992 Polaris Trail Blazer 250\u003cbr\u003e\n1992 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1993 Polaris Trail Blazer 250\u003cbr\u003e\n1993 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1994 Polaris Trail Blazer 250\u003cbr\u003e\n1994 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1995 Polaris Trail Blazer 250\u003cbr\u003e\n1995 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1996 Polaris Trail Blazer 250\u003cbr\u003e\n1996 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1997 Polaris Trail Blazer 250\u003cbr\u003e\n1997 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1998 Polaris Trail Blazer 250\u003cbr\u003e\n1998 Polaris Trail Boss 250 2X4\u003cbr\u003e\n1999 Polaris Trail Blazer 250\u003cbr\u003e\n1999 Polaris Trail Boss 250 2X4\u003cbr\u003e\n2000 Polaris Trail Blazer 250\u003cbr\u003e\n2000 Polaris Xplorer 250 4X4\u003cbr\u003e\n2001 Polaris Trail Blazer 250\u003cbr\u003e\n2001 Polaris Xplorer 250 4X4\u003cbr\u003e\n2002 Polaris Trail Blazer 250\u003cbr\u003e\n2002 Polaris Xplorer 250 4X4\u003cbr\u003e\n2003 Polaris Trail Blazer 250\u003cbr\u003e\n2004 Polaris Trail Blazer 250\u003cbr\u003e\n2005 Polaris Trail Blazer 250\u003cbr\u003e\n2006 Polaris Trail Blazer 250","brand":"NAMURA","offers":[{"title":"Default Title","offer_id":67558807109867,"sku":"186-50006","price":115.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0611\/3882\/9547\/files\/dd77-572a583cd9540_93ad1804-3dea-46df-9b3d-36391d1d9073.jpg?v=1790769023","url":"https:\/\/ctracingservices.com\/products\/namura-na-50000-6k-top-end-kit-73-46-mm-1-50-mm-11-1-compression-for-polaris-250","provider":"Cascade Tire \u0026 Racing Services","version":"1.0","type":"link"}