{"product_id":"lexmoto-lsm-125-k154fmi-57-4mm-big-bore-cylinder-kit-00105-eng","title":"Lexmoto LSM 125 K154FMI 57.4mm Big Bore Cylinder Piston Kit","description":"\u003ch2\u003eLexmoto LSM 125 K154FMI 57.4mm Big Bore Cylinder Piston Kit\u003c\/h2\u003e\n\n\u003cp\u003eBrand new aftermarket big-bore cylinder and piston kit for the \u003cstrong\u003eLexmoto LSM 125 (STR125YB)\u003c\/strong\u003e when fitted with its original \u003cstrong\u003eK154FMI\u003c\/strong\u003e Yamaha\/YBR-pattern engine.\u003c\/p\u003e\n\n\u003ch3\u003eDirect Fitment\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eLexmoto LSM 125 — STR125YB — K154FMI engine\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eKey Specification\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eNominal bore: 57.4 mm\u003c\/li\u003e\n\u003cli\u003ePiston pin: 15 mm\u003c\/li\u003e\n\u003cli\u003eEngine family: K154FMI \/ 154FMI Yamaha-YBR-pattern 125cc engine\u003c\/li\u003e\n\u003cli\u003eCooling: Air-cooled\u003c\/li\u003e\n\u003cli\u003eEngine type: Single-cylinder, four-stroke\u003c\/li\u003e\n\u003cli\u003eBig-bore application: commonly marketed as a 150cc-style conversion\u003c\/li\u003e\n\u003cli\u003eCondition: Brand New aftermarket upgrade\/rebuild part\u003c\/li\u003e\n\u003cli\u003eSKU: 00105-ENG\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhy This Model Is Included\u003c\/h3\u003e\n\u003cp\u003eLexmoto specifies the LSM 125 STR125YB with a K154FMI engine. Aftermarket YBR-pattern big-bore kits are specifically catalogued for 154FMI engines using the same general cylinder family and a 15 mm piston pin.\u003c\/p\u003e\n\n\u003ch3\u003eImportant Compatibility Check\u003c\/h3\u003e\n\u003cp\u003e\u003cstrong\u003eDo not order solely from the model name.\u003c\/strong\u003e Before fitting, compare the original cylinder and engine with the kit shown and confirm:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eK154FMI \/ compatible 154FMI engine code\u003c\/li\u003e\n\u003cli\u003e15 mm piston pin\u003c\/li\u003e\n\u003cli\u003eCylinder height and lower spigot dimensions\u003c\/li\u003e\n\u003cli\u003eHead-stud spacing\u003c\/li\u003e\n\u003cli\u003eCam-chain tunnel position\u003c\/li\u003e\n\u003cli\u003eOil-passage arrangement\u003c\/li\u003e\n\u003cli\u003eBase and head gasket profiles\u003c\/li\u003e\n\u003cli\u003eCrankcase opening clearance for the larger cylinder liner\/spigot\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eModels Not Included\u003c\/h3\u003e\n\u003cp\u003eThe Lexmoto Aspire 125 and ZSF 125 are \u003cstrong\u003enot\u003c\/strong\u003e included in this listing. Lexmoto specifies those bikes with a 156FMI-3 YBR-style engine, including a different standard bore\/stroke specification, so they should not be assumed to use this K154FMI\/YBR big-bore kit.\u003c\/p\u003e\n\n\u003ch3\u003eFuelling \u0026amp; Installation\u003c\/h3\u003e\n\u003cp\u003eA big-bore conversion changes airflow, compression and fuelling requirements. Carburettor jetting may require adjustment. Correct piston-ring orientation, cam timing, valve clearances, gasket preparation and running-in procedure are essential. Professional installation is recommended.\u003c\/p\u003e\n\n\u003ch3\u003eRoad-Use Note\u003c\/h3\u003e\n\u003cp\u003eIncreasing engine capacity can affect registration, insurance, licence entitlement and emissions compliance. The owner is responsible for confirming the legal requirements applicable to the motorcycle.\u003c\/p\u003e\n\n\u003ch3\u003eShipping Estimate\u003c\/h3\u003e\n\u003cp\u003eShopify shipping estimate: approximately 2.2 kg packed, with estimated parcel dimensions of 22 x 20 x 15 cm. Replace these estimates with measured packed weight and dimensions when available.\u003c\/p\u003e","brand":"Unbranded","offers":[{"title":"Default Title","offer_id":57504625951095,"sku":"00105-ENG","price":36.0,"currency_code":"SHP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0528\/8771\/6007\/files\/20260929_085636.jpg?v=1790774912","url":"https:\/\/www.motomaniauk.com\/products\/lexmoto-lsm-125-k154fmi-57-4mm-big-bore-cylinder-kit-00105-eng","provider":"Moto Mania UK","version":"1.0","type":"link"}