{"product_id":"keeway-rks-125-57mm-cylinder-piston-kit-157fmi","title":"Keeway RKS 125 57mm Cylinder \u0026 Piston Kit – 157FMI Type","description":"\u003ch2\u003eKeeway RKS 125 57mm Cylinder \u0026amp; Piston Kit – 157FMI Type\u003c\/h2\u003e\u003cp\u003eBrand-new unbranded standard 57 mm cylinder, piston, ring and gasket kit for compatible Keeway RKS 125 applications using the 157FMI GS-style engine family.\u003c\/p\u003e\u003ch3\u003eKey Specifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eStandard bore: 57 mm\u003c\/li\u003e\n\u003cli\u003eEngine family: K157FMI \/ 157FMI GS-style\u003c\/li\u003e\n\u003cli\u003eStroke reference: 48.8 mm where documented\u003c\/li\u003e\n\u003cli\u003ePiston-pin reference: 14 mm\u003c\/li\u003e\n\u003cli\u003eAir-cooled single-cylinder 4-stroke application\u003c\/li\u003e\n\u003cli\u003eEGR \/ secondary-air-system style cylinder family\u003c\/li\u003e\n\u003cli\u003eCondition: Brand new\u003c\/li\u003e\n\u003cli\u003eType: Unbranded aftermarket replacement\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e1 x cylinder barrel\u003c\/li\u003e\n\u003cli\u003e1 x piston\u003c\/li\u003e\n\u003cli\u003e1 x piston ring set\u003c\/li\u003e\n\u003cli\u003eHead and base gaskets\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eVehicle Compatibility\u003c\/h3\u003e\u003ctable\u003e\n\u003cthead\u003e\u003ctr\u003e\n\u003cth\u003eModel\u003c\/th\u003e\n\u003cth\u003eYears \/ Variant\u003c\/th\u003e\n\u003cth\u003eNotes\u003c\/th\u003e\n\u003c\/tr\u003e\u003c\/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003eRKS 125 \/ RKS Classic\u003c\/td\u003e\n\u003ctd\u003e2011–2017\u003c\/td\u003e\n\u003ctd\u003eOEM cylinder 139013210030; 57 mm \/ 14 mm piston family\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003ctd\u003eRKS 125 EFI \/ RKS Sport EFI\u003c\/td\u003e\n\u003ctd\u003e2017–2020 verified\u003c\/td\u003e\n\u003ctd\u003e57 mm \/ 14 mm piston family; compare OEM cylinder revision and secondary-air ports\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\u003ch3\u003eImportant Fitment Information\u003c\/h3\u003e\u003cp\u003eKeeway RKS engines are documented as 157FMI-2A\/2B rather than every version being stamped exactly K157FMI. The critical top-end evidence is the 57 mm bore, 14 mm piston pin and matching EGR\/secondary-air cylinder layout. Compare the original cylinder before ordering.\u003c\/p\u003e\u003cp\u003eDo not order by 125cc capacity alone. Compare bore, piston-pin diameter, piston crown, cylinder height, stud spacing, gasket profile, oil passages and EGR\/secondary-air ports with the original top end.\u003c\/p\u003e\u003ch3\u003eInstallation\u003c\/h3\u003e\u003cp\u003eCorrect piston-ring orientation, piston direction, valve timing, gasket installation and cylinder-head torque are essential. Professional installation is recommended where the correct engine-building procedure is not known.\u003c\/p\u003e","brand":"Unbranded","offers":[{"title":"Default Title","offer_id":57504411124087,"sku":"01242-ENG","price":44.0,"currency_code":"SHP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0528\/8771\/6007\/files\/20260929_113018.jpg?v=1790772653","url":"https:\/\/www.motomaniauk.com\/products\/keeway-rks-125-57mm-cylinder-piston-kit-157fmi","provider":"Moto Mania UK","version":"1.0","type":"link"}