{"product_id":"athena-big-bore-cylinder-kit-293cc-yamaha-yz250-2003-2026","title":"Athena Big Bore Cylinder Kit (293cc) | Yamaha YZ250 (2003–2026)","description":"\u003cdiv id=\"p-rc_55f0b5f49b210f99-20\"\u003e\n\u003cdiv data-olk-copy-source=\"MailCompose\"\u003eUnlock the raw power your Yamaha YZ250 was built for. The \u003cb\u003eAthena P400485100042 Big Bore Kit\u003c\/b\u003e is a complete, bolt-on performance solution that increases your displacement to \u003cb\u003e293cc\u003c\/b\u003e without requiring permanent engine modifications.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-21\"\u003e\n\u003cdiv\u003eDesigned and engineered in Italy, this kit provides a significant boost in torque and horsepower across the entire power curve while maintaining the legendary reliability of your YZ250.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eKey Performance Benefits\u003c\/b\u003e\u003c\/div\u003e\n\u003cul data-path-to-node=\"7\"\u003e\n\u003cli\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-22\" role=\"presentation\"\u003e\n\u003cdiv\u003e\n\u003cb\u003eMassive Displacement Increase:\u003c\/b\u003e Steps up from the stock 250cc to a potent \u003cb\u003e293cc\u003c\/b\u003e via a 72mm bore.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-23\" role=\"presentation\"\u003e\n\u003cdiv\u003e\n\u003cb\u003eSuperior Cooling:\u003c\/b\u003e Features redesigned, widened water jackets that provide a higher flow rate to keep engine temperatures stable under race conditions.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-24\" role=\"presentation\"\u003e\n\u003cdiv\u003e\n\u003cb\u003eEngineered for Durability:\u003c\/b\u003e The light aluminum alloy cylinder is lined with \u003cb\u003eMotor-Nicksil\u003c\/b\u003e (nickel-silicon coating) for exceptional smoothness and wear resistance.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-25\" role=\"presentation\"\u003e\n\u003cdiv\u003e\n\u003cb\u003eRace-Ready Piston:\u003c\/b\u003e Includes a forged piston with a molybdenum coating to reduce friction and extend the life of your top end.\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cdiv\u003e\u003cb\u003eTechnical Specifications\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003e\n\u003ctable data-path-to-node=\"9\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eFeature\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eDetails\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eBore Diameter\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003e72.00 mm\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eDisplacement\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003e293.2 cc\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eCompression Ratio\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003e15.0:1\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eWheel Power\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003eApprox. 45.3 HP \/ 7600 rpm\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cdiv\u003e\u003cb\u003eInstallation\u003c\/b\u003e\u003c\/div\u003e\n\u003c\/td\u003e\n\u003ctd\u003e\n\u003cdiv\u003eBolt-on (No machining required)\u003c\/div\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\u003cb\u003eWhat’s in the Box?\u003c\/b\u003e\u003c\/div\u003e\n\u003cdiv\u003eThis comprehensive kit includes everything needed for a seamless installation:\u003c\/div\u003e\n\u003cul data-path-to-node=\"12\"\u003e\n\u003cli\u003e\n\u003cdiv role=\"presentation\"\u003eHigh-quality Aluminum Cylinder (72mm)\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv role=\"presentation\"\u003eCylinder Head \u0026amp; Exhaust Valve Kit\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv id=\"p-rc_55f0b5f49b210f99-26\" role=\"presentation\"\u003e\n\u003cdiv\u003eForged Piston, Rings, Pin, and Clips\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv role=\"presentation\"\u003eAthena High-Performance Gasket Set (Top End)\u003c\/div\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cdiv role=\"presentation\"\u003eStep-by-step installation instructions\u003c\/div\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cblockquote\u003e\n\u003cdiv\u003e\n\u003cb\u003ePro Tip:\u003c\/b\u003e To achieve maximum performance gains, we recommend re-jetting your carburetor and using the specific Athena gaskets included in the kit.\u003c\/div\u003e\n\u003c\/blockquote\u003e\n\u003chr\u003e\n\u003cdiv\u003e\n\u003cb\u003eCompatible with:\u003c\/b\u003e Yamaha YZ250 (Years 2003, 2004, 2005... through 2026).\u003c\/div\u003e","brand":"PSS Racing","offers":[{"title":"Default Title","offer_id":44664117133381,"sku":"P400485100042","price":36885.0,"currency_code":"ZAR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0687\/9349\/9717\/files\/athena4.webp?v=1771839225","url":"https:\/\/pssracing.co.za\/products\/athena-big-bore-cylinder-kit-293cc-yamaha-yz250-2003-2026","provider":"PSS Racing","version":"1.0","type":"link"}