{"product_id":"156fmi-157fmi-cg125-56-5mm-15mm-cylinder-piston-kit","title":"156FMI 157FMI CG125-Based 56.5mm 15mm Cylinder Piston Kit","description":"\u003ch2\u003e156FMI \/ 157FMI CG125-Based 56.5mm \/ 15mm Cylinder Kit\u003c\/h2\u003e\n\u003cp\u003eAftermarket cylinder \/ barrel and piston kit for selected Chinese-made 125cc vertical engines based on the CG125 platform, where the original engine uses a 56.5 mm bore and 15 mm piston pin.\u003c\/p\u003e\n\n\u003ch3\u003eTechnical Specification\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003ePart type: Standard-bore cylinder \/ barrel and piston top-end rebuild kit\u003c\/li\u003e\n\u003cli\u003eEngine family: Honda CG125-style air-cooled OHV \/ pushrod 4-stroke single\u003c\/li\u003e\n\u003cli\u003eNominal displacement: \u003cstrong\u003e124cc \/ 125cc\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eStandard bore: \u003cstrong\u003e56.50 mm\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eStroke of the classic CG125 engine family: \u003cstrong\u003e49.50 mm\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003ePiston pin \/ gudgeon pin diameter: \u003cstrong\u003e15 mm\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eTypical old-model CG125 piston overall length: approx. \u003cstrong\u003e52 mm\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eTypical old-model CG125 piston crown height: approx. \u003cstrong\u003e15.5 mm\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003cli\u003eCooling: Air cooled\u003c\/li\u003e\n\u003cli\u003eCondition: Brand new aftermarket replacement\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eImportant Engine-Type Correction\u003c\/h3\u003e\n\u003cp\u003eThe classic Honda CG125 was designed around a short-pushrod \u003cstrong\u003eOHV\u003c\/strong\u003e engine. Honda's own development history and period specifications describe the CG125 as an OHV \/ pushrod engine. Some generic aftermarket adverts incorrectly call similar 56.5 mm kits “OHC”. This listing does \u003cstrong\u003enot\u003c\/strong\u003e rely on that inaccurate wording.\u003c\/p\u003e\n\n\u003ch3\u003eWhat This Kit Is For\u003c\/h3\u003e\n\u003cp\u003eThis kit is intended for a standard-bore top-end rebuild where the original cylinder or piston is worn, scored or damaged, compression is low, or the engine is being restored. The 56.5 mm bore and 15 mm piston pin are critical fitment dimensions.\u003c\/p\u003e\n\n\u003ch3\u003eTypical Kit Contents\u003c\/h3\u003e\n\u003cp\u003eThe source listing identifies a cylinder \/ barrel and piston kit. Comparable kits in this exact 56.5 mm \/ 15 mm family commonly include:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003e1 x cylinder \/ barrel\u003c\/li\u003e\n\u003cli\u003e1 x 56.5 mm piston\u003c\/li\u003e\n\u003cli\u003ePiston ring set\u003c\/li\u003e\n\u003cli\u003e15 mm gudgeon \/ wrist pin\u003c\/li\u003e\n\u003cli\u003ePiston-pin circlips\u003c\/li\u003e\n\u003cli\u003eHead and base gaskets\u003c\/li\u003e\n\u003cli\u003eSome kits also include valve-stem seals\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eUse the listing photographs as the final guide to the exact components supplied with SKU 00921-ENG.\u003c\/strong\u003e Do not assume every item listed above is included if it is not visible in your stock photographs.\u003c\/p\u003e\n\n\u003ch3\u003eCritical Fitment Checks\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eMeasure the existing cylinder bore: this kit is \u003cstrong\u003e56.50 mm standard bore\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003eMeasure the piston pin: this kit is the \u003cstrong\u003e15 mm pin\u003c\/strong\u003e version.\u003c\/li\u003e\n\u003cli\u003eCompare cylinder overall \/ effective height, crankcase spigot, stud spacing and oil-way arrangement.\u003c\/li\u003e\n\u003cli\u003eCompare piston crown, compression height and ring layout.\u003c\/li\u003e\n\u003cli\u003eConfirm the engine is the CG125-style OHV \/ pushrod architecture and not a visually similar OHC \/ YBR-type 125 engine.\u003c\/li\u003e\n\u003cli\u003eLater CG125 \/ CG125ES \/ XR125-style applications can use a \u003cstrong\u003e13 mm piston pin\u003c\/strong\u003e and different KGA-series cylinder \/ piston parts. Do not fit this 15 mm kit to a 13 mm-pin engine.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eInstallation Guidance\u003c\/h3\u003e\n\u003cp\u003eTop-end assembly requires correct piston orientation, ring positioning, circlip installation, gasket alignment, valve adjustment and cylinder-head torque. Check the connecting-rod small end and piston-pin fit before assembly. Lubricate the bore and piston during installation, rotate the engine by hand before starting, and use an appropriate running-in procedure after rebuilding.\u003c\/p\u003e\n\u003cp\u003eProfessional fitting is recommended if you are not experienced with OHV motorcycle engines.\u003c\/p\u003e\n\n\u003ch3\u003ePackage \/ Brand Note\u003c\/h3\u003e\n\u003cp\u003eThis is an aftermarket \/ unbranded replacement part. Honda names and engine references are used only to identify the intended application and are not a claim that the product is Genuine Honda.\u003c\/p\u003e\n\n\u003ch3\u003eDocumented \/ Supported Fitment\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eSelected 156FMI CG125-based 125cc engines\u003c\/li\u003e\n\u003cli\u003eSelected Chinese CG125-based 157FMI engines, commonly catalogued in the 2002-2011 period\u003c\/li\u003e\n\u003cli\u003e56.50 mm standard bore and 15 mm piston-pin requirement\u003c\/li\u003e\n\u003cli\u003eUsed on various Chinese-made motorcycles and ATVs depending on the exact engine sub-type\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFitment note:\u003c\/strong\u003e Engine codes are not sufficiently specific on their own. Some engines labelled 156FMI \/ 157FMI are YBR\/OHC or other designs with different bore or cylinder architecture. Only use this listing where the actual engine is the CG125-style OHV \/ pushrod 56.5 mm \/ 15 mm-pin version.\u003c\/p\u003e\n","brand":"Unbranded","offers":[{"title":"Default Title","offer_id":57504786743671,"sku":"00921-ENG","price":51.0,"currency_code":"SHP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0528\/8771\/6007\/files\/20260929_141436.jpg?v=1790782393","url":"https:\/\/www.motomaniauk.com\/products\/156fmi-157fmi-cg125-56-5mm-15mm-cylinder-piston-kit","provider":"Moto Mania UK","version":"1.0","type":"link"}