{"product_id":"namura-040-over-bore-top-end-repair-kit-for-yamaha-yz250-1999-2001-67-4mm","title":"Namura .040 Over Bore Top End Repair Kit for Yamaha YZ250 1999-2001 67.4mm","description":"\u003ch2\u003e.040 Over Bore Top End Repair Kit for Yamaha YZ250\u003c\/h2\u003e\u003cp\u003eThis top end repair kit for Yamaha YZ250 provides all necessary components for a .040 over bore rebuild, including piston, rings, wrist pin, and gasket set.\u003c\/p\u003e\u003ch4\u003eOverview\u003c\/h4\u003e\u003cp\u003eThe Namura top end repair kit is designed for Yamaha YZ250 models from 1999 to 2001, delivering reliable performance for off-road racing and trail riding. With a 67.4mm bore size (.040 over standard), this kit restores compression and power. It is a cost-effective alternative to OEM components while meeting factory specifications.\u003c\/p\u003e\u003ch4\u003eBuilt For Performance\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003ePrecision-cast piston matched to 67.4mm bore for optimal compression\u003c\/li\u003e\n\u003cli\u003eChrome-plated steel rings provide long wear and consistent sealing\u003c\/li\u003e\n\u003cli\u003eComplete gasket set includes base gasket, head gasket, and exhaust gasket\u003c\/li\u003e\n\u003cli\u003eHeat-treated wrist pin with c-clips for secure connection\u003c\/li\u003e\n\u003cli\u003eBalanced piston weight reduces vibration and improves engine smoothness\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eFits These Machines\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003efor Yamaha YZ250 (1999)\u003c\/li\u003e\n\u003cli\u003efor Yamaha YZ250 (2000)\u003c\/li\u003e\n\u003cli\u003efor Yamaha YZ250 (2001)\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch4\u003eOn-The-Job Use\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003eMotocross racing where top-end power and reliability are critical\u003c\/li\u003e\n\u003cli\u003eTrail riding and enduro competitions requiring consistent performance\u003c\/li\u003e\n\u003cli\u003eTwo-stroke engine rebuilds for restoring worn top ends\u003c\/li\u003e\n\u003cli\u003eHigh-performance riding demanding precise piston-to-cylinder clearance\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 in\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eEngine\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003eYamaha YZ250 2-stroke\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\u003cstrong\u003eCompatible Years\u003c\/strong\u003e\u003c\/td\u003e\n\u003ctd\u003e1999-2001\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 Can I use this kit on a 2002 Yamaha YZ250? \u003cstrong\u003eA:\u003c\/strong\u003e No, this kit is specifically designed for 1999-2001 models; later years have different cylinder porting and bore dimensions.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Do I need to replace the cylinder when using this overbore kit? \u003cstrong\u003eA:\u003c\/strong\u003e If your cylinder is within service limits, it can be reused after honing to match the 67.4mm piston; always measure before installation.\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":44890908491862,"sku":"SZ1F13562","price":175.89,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0697\/8460\/0662\/files\/1_46791512-2ca8-462b-ba8f-d7b4a6255c89.jpg?v=1781144280","url":"https:\/\/www.solidspare.com\/products\/namura-040-over-bore-top-end-repair-kit-for-yamaha-yz250-1999-2001-67-4mm","provider":"Solid Spare","version":"1.0","type":"link"}