{"product_id":"namura-nx-40026-bk-top-end-kit-for-1992-1994-yamaha-yz250-67-95-mm-ceramic-composite-piston","title":"Namura NX-40026-BK Top End Kit for 1992–1994 Yamaha YZ250, 67.95 mm Ceramic-Composite Piston","description":"\u003cp\u003eThe Namura NX-40026-BK Top End Kit is designed for 1992, 1993, and 1994 Yamaha YZ250 two-stroke motorcycles. This 67.95 mm ceramic-composite top end kit includes the piston, piston rings, wrist pin, retaining clips, top-end bearing, and gasket kit needed for a comprehensive upper-engine rebuild. The kit is engineered for dependable fitment and performance in the original Yamaha YZ250 cylinder application.\u003c\/p\u003e\u003cp\u003eNamura uses a hypereutectic casting process to provide increased silicon content, helping reduce thermal expansion while improving wear resistance and the piston’s ability to withstand elevated cylinder temperatures. The piston features MOS2, or Teflon\/molybdenum, coated skirts applied with a rolled-on process for a durable bond. This coating helps improve heat transfer, reduce friction, and minimize the risk of cold seizures during operation.\u003c\/p\u003e\u003cp\u003eThe machined smooth piston head helps reflect combustion heat and reduce carbon buildup, supporting piston durability and protecting the top of the piston. An anodized dome further improves heat resistance and strength compared with non-anodized piston designs. With an 11:1 compression ratio, this Namura top end kit is a practical replacement solution for restoring engine performance and service life on compatible Yamaha YZ250 models. Manufacturer part number NX-40026-BK; vendor part number 185-4026B.\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\u003e67.95 mm ceramic-composite piston for compatible Yamaha YZ250 applications\u003c\/li\u003e\n\u003cli\u003eMOS2 Teflon\/molybdenum-coated skirts help 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 reduced expansion, increased wear resistance, and improved high-temperature capability\u003c\/li\u003e\n\u003cli\u003e11:1 compression ratio\u003c\/li\u003e\n\u003cli\u003eFits 1992 Yamaha YZ250, 1993 Yamaha YZ250, and 1994 Yamaha YZ250\u003c\/li\u003e\n\u003cli\u003eBrand: Namura\u003c\/li\u003e\n\u003cli\u003eManufacturer part number: NX-40026-BK\u003c\/li\u003e\n\u003cli\u003eVendor part number: 185-4026B\u003c\/li\u003e\n\u003c\/ul\u003e\u003cbr\u003e\nFitment:\u003cbr\u003e\n1992 Yamaha YZ250\u003cbr\u003e\n1993 Yamaha YZ250\u003cbr\u003e\n1994 Yamaha YZ250","brand":"NAMURA","offers":[{"title":"Default Title","offer_id":67559772553451,"sku":"185-4026B","price":120.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0611\/3882\/9547\/files\/dd77-572a583cd9540_35ef890a-434a-4094-aabb-0117e692469b.jpg?v=1790772952","url":"https:\/\/ctracingservices.com\/products\/namura-nx-40026-bk-top-end-kit-for-1992-1994-yamaha-yz250-67-95-mm-ceramic-composite-piston","provider":"Cascade Tire \u0026 Racing Services","version":"1.0","type":"link"}