{"product_id":"athena-p400485100030-144cc-big-bore-cylinder-kit-with-cylinder-head-58mm-bore-premium-2-stroke-performance-upgrade-compatible-with-yamaha-yz125-2005-2021","title":"Athena P400485100030 144cc Big Bore Cylinder Kit with Cylinder Head (58mm Bore) - Premium 2-Stroke Performance Upgrade, Compatible with Yamaha YZ125 2005-2021","description":"UPGRADE YOUR DIRT BIKE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low-end torque, and unmatched acceleration from your modern aluminum-frame 125cc two-stroke racing engine with the Athena Big Bore Cylinder Kit (Part No. P400485100030), a premium race-proven package engineered in Italy to seamlessly convert your factory setup into a high-revving, high-output 144cc powerhouse. Entirely cast from high-grade aluminum and treated with a specialized Motor-Nicksil (Nickel-Silicon) coating, this cylinder guarantees exceptional thermal dissipation, minimal friction, and optimal wear resistance to deliver a substantial increase along the entire power curve while maintaining strict original-equipment reliability. This complete bolt-on kit comes loaded with everything required for a flawless installation—including a precision-machined 58mm big bore cylinder, a dedicated high-compression cylinder head, updated clearanced power valve hardware, a premium cast piston assembly, rings, wrist pin, clips, and a specific high-tightness multi-layer gasket set—allowing you to dramatically increase track performance without requiring any complex machining or structural modifications to your factory crankcase.","brand":"Athena","offers":[{"title":"Default Title","offer_id":52665925173535,"sku":"P400485100030","price":1131.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0813\/2195\/1519\/files\/P400485100030-1.jpg?v=1783599167","url":"https:\/\/massdepot.com\/products\/athena-p400485100030-144cc-big-bore-cylinder-kit-with-cylinder-head-58mm-bore-premium-2-stroke-performance-upgrade-compatible-with-yamaha-yz125-2005-2021","provider":"Mass Depot","version":"1.0","type":"link"}