{"product_id":"namura-040-over-bore-piston-kit-for-yamaha-yz250-yz250x-fits-1999-2024-67-4mm","title":"Namura .040 Over Bore Piston Kit for Yamaha YZ250 \u0026 YZ250X fits 1999-2024 67.4mm","description":"\u003ch2\u003eNamura .040 Over Bore Piston Kit for Yamaha\u003c\/h2\u003e\u003cp\u003eThis .040 over bore piston kit is designed to restore compression in Yamaha YZ250 and YZ250X engines from 1999 to 2024 with a 67.4mm bore.\u003c\/p\u003e\u003ch4\u003eOverview\u003c\/h4\u003e\u003cp\u003eThe Namura .040 over bore piston kit is a direct replacement for worn pistons in Yamaha two-stroke engines. This piston kit provides reliable power and durability for off-road and motocross riding. It is engineered for Yamaha YZ250 and YZ250X models requiring a 67.4mm bore.\u003c\/p\u003e\u003ch4\u003eBuilt For Performance\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eForged 4032 aluminum alloy for high strength and thermal stability\u003c\/li\u003e\n\u003cli\u003eIncludes piston rings, wrist pin, and circlips for a complete replacement\u003c\/li\u003e\n\u003cli\u003ePrecision machined to 67.4mm for .040 over bore applications\u003c\/li\u003e\n\u003cli\u003eAdvanced skirt coating reduces friction and wear\u003c\/li\u003e\n\u003cli\u003eDesigned for high-rpm performance in two-stroke engines\u003c\/li\u003e\n\u003cli\u003eWeight-matched for consistent engine balance\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eFits These Machines\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003efor Yamaha YZ250 (1999-2024)\u003c\/li\u003e\n\u003cli\u003efor Yamaha YZ250X (1999-2024)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eOn-The-Job Use\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eRestores lost compression in high-mileage YZ250 engines\u003c\/li\u003e\n\u003cli\u003eIdeal for motocross and off-road racing rebuilds\u003c\/li\u003e\n\u003cli\u003eUsed in top-end rebuilds for improved throttle response\u003c\/li\u003e\n\u003cli\u003eRecommended for competition-level two-stroke maintenance\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eSpecs At A Glance\u003c\/h4\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eBore Size\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e67.4mm\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eOverbore\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e.040 inch\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003ePiston Material\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eForged Aluminum\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eIncluded Components\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003ePiston, Rings, Wrist Pin, Circlips\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch4\u003eGood To Know\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Is this piston kit a direct replacement for the OEM piston? \u003cstrong\u003eA:\u003c\/strong\u003e This kit is a direct replacement when the cylinder is bored to .040 over size. Confirm your cylinder bore before ordering.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e What is the recommended break-in procedure? \u003cstrong\u003eA:\u003c\/strong\u003e After installation, follow a standard two-stroke break-in with varying throttle loads for the first hour of operation.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eSlight variation in finish or dimensions may occur between production runs, and fit can depend on serial number, so confirm compatibility before ordering.\u003c\/em\u003e\u003c\/p\u003e","brand":"Solid Spare","offers":[{"title":"Default Title","offer_id":44890494206038,"sku":"SZ1F11943","price":138.59,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0697\/8460\/0662\/files\/1_bef8b16a-7639-4759-8e52-0703852e8dbe.jpg?v=1781140726","url":"https:\/\/www.solidspare.com\/products\/namura-040-over-bore-piston-kit-for-yamaha-yz250-yz250x-fits-1999-2024-67-4mm","provider":"Solid Spare","version":"1.0","type":"link"}