{"product_id":"athena-p400210100067-290cc-big-bore-cylinder-kit-85mm-bore-co-fused-steel-liner-forged-piston-upgrade-converts-250cc-to-289cc-compatible-with-honda-crf250r-crf250rx-2018-2021","title":"Athena P400210100067 290cc Big Bore Cylinder Kit (85mm Bore) - Co-Fused Steel Liner Forged Piston Upgrade, Converts 250cc to 289cc, Compatible with Honda CRF250R \u0026 CRF250RX 2018-2021","description":"UPGRADE YOUR DIRT BIKE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low-end torque, and unmatched acceleration from your 250cc four-stroke engine with the Athena Big Bore Cylinder Kit (Part No. P400210100067), a premium race-proven package engineered in Italy to seamlessly convert your factory setup into a high-revving, high-output 290cc (289cc actual) powerhouse. Utilizing an innovative co-fusion production process that integrates a heavy-duty steel sleeve directly into an aluminum outer casting, this unique cylinder maximizes internal bore geometry without requiring structural modifications or machining to your factory crankcase. Lined with a high-durability galvanic nickel-silicon treatment, this setup ensures maximum heat dissipation, reduced mechanical friction, and optimal wear resistance. The complete bolt-on kit comes fully loaded with everything needed for installation—including the advanced hybrid cylinder, a lightweight box-bridged forged piston coated in friction-reducing molybdenum disulfide, a biconical DLC-coated wrist pin, premium rings, wire locks, and a multi-layer high-tightness gasket set—delivering full-bodied torque across all steady states while preserving your bike's agile handling.","brand":"Mass Depot","offers":[{"title":"Default Title","offer_id":52657770529055,"sku":"P400210100067","price":1079.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0813\/2195\/1519\/files\/P400210100067-1.jpg?v=1783341979","url":"https:\/\/massdepot.com\/products\/athena-p400210100067-290cc-big-bore-cylinder-kit-85mm-bore-co-fused-steel-liner-forged-piston-upgrade-converts-250cc-to-289cc-compatible-with-honda-crf250r-crf250rx-2018-2021","provider":"Mass Depot","version":"1.0","type":"link"}