{"product_id":"vertex-22584a-piston-kit-yamaha-yz250-moto-house-mx","title":"Vertex Cast Replica Piston Kit (66.34mm\/66.35mm) 22584A \/ 22584B — Yamaha YZ250 \/ YZ250X 1999-2024","description":"\u003ch1\u003e\u003cstrong\u003eVertex Cast Replica Piston Kit (66.34mm\/66.35mm) 22584A \/ 22584B — Yamaha YZ250 \/ YZ250X 1999-2024\u003c\/strong\u003e\u003c\/h1\u003e\n\u003ch2\u003eProduct Description\u003c\/h2\u003e\n\u003cp\u003eThe Vertex Cast Replica Piston Kit offers a reliable factory-spec restoration solution for riders renewing the top-end performance of their Yamaha YZ250 and YZ250X. Engineered as an exact OE replacement piston package, this setup restores original engine compression, cylinder seal, and throttle response to keep your legendary 2-stroke engine pulling hard out of the corners.\u003c\/p\u003e\n\u003cp\u003eConstructed using gravity-cast aluminum alloy infused with an 18% silicone content, this structural composition limits thermal expansion and preserves precise cylinder clearances. The entire structure undergoes a T-5 hardening and tempering cycle to maximize structural integrity, while the piston skirt features a specialized Molybdenum Disulphite coating designed to accelerate initial break-in times and protect against cold-start wear. This comprehensive kit bundles the replacement piston, high-tension rings, wrist pin, and securing circlips for an efficient overhaul assembly.\u003c\/p\u003e\n\u003ch3\u003eTop Features: Vertex Cast Replica Piston Kit\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eGravity-cast aluminum alloy formulation with 18% silicone content holds uniform profile under extreme heat.\u003c\/li\u003e\n\u003cli\u003eAdvanced T-5 thermal hardening and tempering cycle optimizes mechanical strength and cylinder longevity.\u003c\/li\u003e\n\u003cli\u003eMolybdenum Disulphite skirt coating reduces internal friction coefficients for faster break-in protection.\u003c\/li\u003e\n\u003cli\u003eAll-inclusive top-end package includes a matched piston, precision rings, wrist pin, and circlips.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003ePlease review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.\u003c\/p\u003e\n\u003ch3\u003eFitment List\u003c\/h3\u003e\n\u003ctable style=\"width: 100%; border-collapse: collapse; margin-top: 15px; margin-bottom: 20px; font-family: inherit;\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth style=\"border: 1px solid #e2e8f0; padding: 12px; background-color: #f8fafc; text-align: left; font-weight: bold;\"\u003eYear Range\u003c\/th\u003e\n\u003cth style=\"border: 1px solid #e2e8f0; padding: 12px; background-color: #f8fafc; text-align: left; font-weight: bold;\"\u003eVehicle Brand\u003c\/th\u003e\n\u003cth style=\"border: 1px solid #e2e8f0; padding: 12px; background-color: #f8fafc; text-align: left; font-weight: bold;\"\u003eVehicle Model \u0026amp; Sub-Model\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003e2016-2024\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003eYamaha\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003eYZ250X\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003e1999-2024\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003eYamaha\u003c\/td\u003e\n\u003ctd style=\"border: 1px solid #e2e8f0; padding: 12px;\"\u003eYZ250\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eQ: What is the mechanical difference between the \"A\" and \"B\" piston sizes?\u003c\/strong\u003e\u003cbr\u003eA: The \"A\" size (66.34mm) is intended for fresh factory cylinders or newly replated bores. The \"B\" size (66.35mm) is fractions of a millimeter larger to compensate for light, normal cylinder wall wear over time, allowing you to maintain correct piston-to-wall clearance without replating.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eQ: Why is a cast piston utilized for this application instead of a forged option?\u003c\/strong\u003e\u003cbr\u003eA: Cast pistons feature higher silicone content than forged pistons, allowing them to expand less when exposed to operating temperatures. This stabilizes piston rock inside the cylinder bore, delivering quiet operation and matching original equipment factory tolerances.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eExpert Pro-Tip:\u003c\/strong\u003e Before sliding your new Vertex piston assembly into the cylinder, always measure your ring end-gap inside the clean bore using a feeler gauge. Additionally, ensure you orient the piston with the structural arrow stamped on the crown pointing directly toward the exhaust port. Installing it backward will cause the ring ends to catch on the intake ports, instantly damaging your top end.\u003c\/p\u003e\n\u003ch3\u003eRecommended Pairings:\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/motohousemx.com\/collections\/yamaha-yz250-and-yz250x-performance-parts-collection-at-moto-house-mx\"\u003eYamaha YZ250 \/ YZ250X Performance Parts \u0026amp; Upgrades\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"https:\/\/motohousemx.com\/collections\/yamaha-2-stroke-dirt-bikes-performance-parts-accessories-moto-house-mx\"\u003eYamaha 2-Stroke Performance Parts\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003eAt Moto-House MX, we carry the best brands in motocross and off-road performance. Our team has over 40 years of experience helping riders get more out of their bikes. Every order ships fast from our Central Florida location.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eMoto-House MX – Choice of Champions – Clermont \/ Montverde, FL. Central Florida's premier powersports source with lightning-fast worldwide shipping.\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"Vertex","offers":[{"title":"A Piston Kit - 1999-2025 YZ250","offer_id":39964608528467,"sku":"22584A","price":165.74,"currency_code":"USD","in_stock":true},{"title":"B Piston Kit - 1999-2025 YZ250","offer_id":39964608561235,"sku":"22584B","price":165.74,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1754\/5421\/files\/vertex-oem-cast-replica-piston-1999-2025-yamaha-yz250-2016-2025-yz250x-143727.jpg?v=1739939112","url":"https:\/\/motohousemx.com\/products\/vertex-22584a-piston-kit-yamaha-yz250-moto-house-mx","provider":"Moto-House MX","version":"1.0","type":"link"}