{"product_id":"yamaha-yz125-athena-144cc-big-bore-top-end-kit","title":"05-21 Yamaha YZ125 YZ 125 58mm 144cc Athena Big Bore Cylinder Top End Piston Kit","description":"\u003cmeta name=\"keywords\" content=\"yamaha yz125 athena 144cc big bore kit 58mm yz125 cylinder kit athena yz125 top end kit yz125x 144cc big bore yz125 performance cylinder yz125 nikasil cylinder yz125 complete top end kit athena 58mm cylinder yz125 motocross engine upgrade yz125 big bore conversion\"\u003e\u003cmeta name=\"description\" content=\"Athena 144cc big bore kit for Yamaha YZ125 and YZ125X delivers increased horsepower, torque and reliability with premium performance components.\"\u003e\u003cp style=\"text-align: center;\"\u003e\u003cspan style=\"font-size: 0.000000px; color: transparent;\"\u003eUpgrade your Yamaha YZ125 with Athena's 58mm 144cc big bore top end kit featuring a Nikasil cylinder, coated piston, head, studs and complete gaskets. \u003c\/span\u003e\u003c\/p\u003e\n\u003cdiv style=\"max-width: 800px; margin: 0 auto; font-family: Arial,Helvetica,sans-serif; line-height: 1.5; color: #222;\"\u003e\n\u003ch2 style=\"text-align: center; font-size: 26px; margin: 0 0 12px 0;\"\u003e\u003cstrong\u003e2005-2021 Yamaha YZ125 \/ 2020-2022 YZ125X Athena 58mm 144cc Big Bore Top End Kit\u003c\/strong\u003e\u003c\/h2\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e📖 Product Description\u003c\/h3\u003e\n\u003cp style=\"text-align: center; margin: 0 20px;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e Take your Yamaha YZ125 to the next level with the legendary \u003cstrong\u003eAthena 58mm 144cc Big Bore Top End Kit\u003c\/strong\u003e. Designed for riders looking for a substantial increase in horsepower, torque, and throttle response, this premium kit transforms your 125cc engine into a powerful 144cc machine while maintaining the reliability Athena is known for. \u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"text-align: center; margin: 0 20px;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e Featuring a precision-machined \u003cstrong\u003eNikasil-plated aluminum cylinder\u003c\/strong\u003e, matched coated piston, performance cylinder head, and complete installation hardware, this is one of the most complete and dependable big bore kits available. Whether you're racing motocross, riding trails, or rebuilding your engine, this kit delivers outstanding performance and long service life. \u003c\/span\u003e\u003c\/p\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e🔥 Key Features \u0026amp; Benefits\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eAthena 58mm 144cc Big Bore Cylinder Kit\u003c\/strong\u003e delivers increased horsepower and torque.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eNikasil-plated aluminum cylinder\u003c\/strong\u003e provides superior durability and heat dissipation.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eComplete top end solution\u003c\/strong\u003e with matched piston, cylinder head, gaskets, and hardware.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eDirect bolt-on upgrade\u003c\/strong\u003e with no case machining required.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eIdeal for motocross, woods, and off-road riding\u003c\/strong\u003e requiring stronger low and mid-range power.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003eManufactured by \u003cstrong\u003eAthena\u003c\/strong\u003e, one of the world's leading performance engine manufacturers.\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eAll components are brand new\u003c\/strong\u003e and backed by the manufacturer's warranty.\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e📦 Product Contents\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e1 × \u003cstrong\u003eAthena 58mm Nikasil-Plated 144cc Big Bore Cylinder\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e1 × \u003cstrong\u003eAthena Coated Piston Kit\u003c\/strong\u003e (Piston, Rings, Wrist Pin \u0026amp; Circlips)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e1 × \u003cstrong\u003eAthena Complete Top End Gasket Set\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e1 × \u003cstrong\u003eAthena Performance Cylinder Head\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e1 × \u003cstrong\u003eAthena Head Stud Kit\u003c\/strong\u003e\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e✅ Compatibility\u003c\/h3\u003e\n\u003cp style=\"text-align: center; margin: 0 20px;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e Designed as a direct performance upgrade for the following Yamaha two-stroke models: \u003c\/span\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eYamaha YZ125\u003c\/strong\u003e (2005-2021)\u003c\/span\u003e\u003c\/li\u003e\n\u003cli\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eYamaha YZ125X\u003c\/strong\u003e (2020-2022)\u003c\/span\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e❓ Frequently Asked Questions\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Does this increase the engine to 144cc?\u003c\/span\u003e\n\u003cp style=\"text-align: left; margin: 0 0 10px 0;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes. The 58mm Athena cylinder increases displacement from 125cc to approximately 144cc for significantly improved power and torque.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Is this a complete top end kit?\u003c\/span\u003e\n\u003cp style=\"text-align: left; margin: 0 0 10px 0;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes. The kit includes the cylinder, coated piston kit, cylinder head, head stud kit, and complete top end gasket set.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Does this require machining?\u003c\/span\u003e\n\u003cp style=\"text-align: left; margin: 0 0 10px 0;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eA:\u003c\/strong\u003e No. This kit is engineered as a direct bolt-on performance upgrade for the listed models.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eQ:\u003c\/strong\u003e Are all parts covered by warranty?\u003c\/span\u003e\n\u003cp style=\"text-align: left; margin: 0 0 10px 0;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003cstrong\u003eA:\u003c\/strong\u003e Yes. All Athena components are brand new and covered by the manufacturer's warranty.\u003c\/span\u003e\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3 style=\"color: #c00; margin: 20px 0 6px; text-align: center;\"\u003e🌟 Why Buy from BPRATV\u003c\/h3\u003e\n\u003cp style=\"color: rgb(34,34,34); text-align: center;\"\u003e\u003cspan style=\"font-size: 16px;\"\u003e At \u003cstrong\u003eBPRATV\u003c\/strong\u003e, our promise is unwavering: \u003cstrong\u003eThe Best Parts. The Best Performance. The Best Price.\u003c\/strong\u003e We specialize in high-performance powersports components trusted by riders and builders who demand reliability and results. Every part is carefully selected for precision, durability, and real-world performance. Trust BPRATV to keep your \u003cstrong\u003eYamaha YZ125 or YZ125X\u003c\/strong\u003e running at its best, \u003cstrong\u003eevery single time.\u003c\/strong\u003e \u003c\/span\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"text-align: center; margin: 0 20px;\"\u003e\u003cspan style=\"color: #38761d; font-size: 16px;\"\u003e \u003cstrong\u003e\u003cem\u003eUpgrade your Yamaha YZ125 with Athena's legendary 144cc Big Bore performance--order yours today!\u003c\/em\u003e\u003c\/strong\u003e \u003c\/span\u003e\u003cspan style=\"font-size: 16px;\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp style=\"text-align: center;\"\u003e\u003cspan style=\"color: #0000ff; font-size: 16px;\"\u003e \u003cstrong\u003eBPRATV - The Best Parts. The Best Performance. The Best Price.\u003cbr\u003e\u003c\/strong\u003e\u003c\/span\u003e\u003cstrong style=\"color: rgb(0, 0, 255); font-size: 16px;\"\u003eBRAPPPPPPPPPP!\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp style=\"text-align: center; font-size: 10px; color: #555; margin: 20px 0 50px;\"\u003e© BPRATV LLC\u003cbr\u003e\u003cbr\u003eDue to the nature of high performance and racing applications, BPRATV LLC components are sold without express warranty or any implied warranty of merchantability or fitness for a specific purpose. BPRATV LLC shall not, under any circumstances, be liable for any specific, incidental or consequential damages, including, but not limited to, damage, or loss of property or equipment, loss of profits or revenue(s), cost of purchased or replacement goods, or claims of customers of the purpose, which may arise and\/or shall result from sale, installation or use of these parts. Installation of these parts may void vehicle manufacturers warranty coverage and\/or may cause the vehicle to be illegal in some locations.\u003cbr\u003e\u003cbr\u003eThis product is exempt from the emission standards and related requirements of 40 C.F.R. §1051 as provided by 40 C.F.R. §1051.620, and California law. This product is sold only for use in connection with EPA-certified, purpose-built, nonroad vehicles used solely for closed-course, nonroad competition\/racing.\u003c\/p\u003e\n\u003c\/div\u003e\n\u003c!--\n\n10 eBay Titles\n\n2005-2021 Yamaha YZ125 Athena 144cc Big Bore Cylinder Top End Kit 58mm\nAthena 58mm 144cc Big Bore Top End Kit Yamaha YZ125 YZ125X Performance\nYamaha YZ125 Athena 144cc Big Bore Cylinder Piston Head Kit 2005-2021\n2005-2021 YZ125 Athena 58mm Big Bore Top End Kit Fits YZ125X 2020-2022\nAthena 144cc Big Bore Kit Yamaha YZ125 Cylinder Head Piston Complete\nYamaha YZ125 144cc Big Bore Top End Kit Athena 58mm Nikasil Cylinder\nYZ125 Athena Big Bore Kit 58mm Cylinder Piston Head Gasket Kit Complete\nAthena Yamaha YZ125 Performance 144cc Big Bore Cylinder Kit 2005-2021\nYZ125X Athena 144cc Big Bore Top End Kit Fits 2020-2022 Models\nAthena 58mm Big Bore Cylinder Kit Yamaha YZ125 YZ125X Complete Top End\n\n10 eBay Keywords\n\nyz125 144cc kit\nathena yz125 big bore\nyz125 top end kit\nyz125 cylinder kit\nyz125 piston kit\nyz125x big bore\n58mm yz125 cylinder\nathena 144cc\nyz125 engine rebuild\nyz125 performance kit\n\n10 SEO Keywords\n\nyamaha yz125 athena 144cc big bore kit\n58mm yz125 cylinder kit\nathena yz125 top end kit\nyz125x 144cc big bore\nyz125 performance cylinder\nyz125 nikasil cylinder\nyz125 complete top end kit\nathena 58mm cylinder\nyz125 motocross engine upgrade\nyz125 big bore conversion\n\n10 Meta Titles\n\nAthena 144cc Big Bore Kit Yamaha YZ125 58mm Top End Kit\nYZ125 Athena 58mm Big Bore Cylinder Top End Kit\nAthena 144cc Performance Kit Yamaha YZ125 YZ125X\nYamaha YZ125 Athena Big Bore Cylinder Kit\n58mm Athena Top End Kit Fits Yamaha YZ125\n\n10 Meta Descriptions\n\nUpgrade your Yamaha YZ125 with Athena's 58mm 144cc big bore top end kit featuring a Nikasil cylinder, coated piston, head, studs and complete gaskets.\nAthena 144cc big bore kit for Yamaha YZ125 and YZ125X delivers increased horsepower, torque and reliability with premium performance components.\nComplete Athena top end kit includes a 58mm Nikasil cylinder, coated piston, cylinder head, head studs and gasket set for Yamaha YZ125 models.\nIncrease power with Athena's 144cc big bore conversion kit for Yamaha YZ125 and YZ125X using premium race-proven engine components.\nPremium Athena 58mm big bore top end kit for Yamaha YZ125 includes everything needed for a reliable 144cc performance upgrade.\n\nSEO URL Handles\n\nyamaha-yz125-athena-144cc-big-bore-top-end-kit\nathena-58mm-yz125-big-bore-cylinder-kit\nyz125-144cc-performance-top-end-kit\nyamaha-yz125x-athena-big-bore-kit\nathena-yz125-58mm-cylinder-conversion\n\n--\u003e","brand":"Athena","offers":[{"title":"Default Title","offer_id":42569621078213,"sku":"266541239158\/P400485100030\/JT","price":923.36,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0593\/1083\/3861\/files\/2907f8be-7eb5-4a1f-b190-74cb5e935fab.png?v=1782948776","url":"https:\/\/bpratv.com\/products\/yamaha-yz125-athena-144cc-big-bore-top-end-kit","provider":"BPRATV","version":"1.0","type":"link"}