Lexmoto XTR S 125 KS125-24 58mm Piston Ring Gasket Kit 14mm Pin
Aftermarket top-end piston rebuild kit for Lexmoto XTR S 125 [KS125-24] applications using the compatible 58 mm 158FMI/ZS158FMI-B piston family. Suitable for replacing a worn piston, rings and top-end sealing gaskets where the original dimensions and gasket profiles match.
Components Identified From the Product Photo Set
- 1 x aluminium piston with machined ring grooves
- 1 x piston-ring set including compression and oil-control rings
- 1 x steel gudgeon / wrist pin
- 2 x piston-pin retaining circlips
- 1 x cylinder-head gasket
- 1 x cylinder-base gasket
Key Specification
- Replacement piston family: 58 mm PIST037 / PSTR032 pattern
- Piston-ring diameter: 58 mm
- Engine type: Air-cooled 4-stroke single cylinder
- Engine reference: 156FMI / 156FMI OHC CBB balance-shaft family
- Model code: KS125-24
- Condition: New aftermarket replacement
Manufacturer & OE-Style Cross-References
- Piston family — CMPO PIST037: 58 mm piston family identified by the matching PSTR032 ring set
- Piston rings — CMPO PSTR032: 58 mm, 4-stroke; EAN 5057645142348; reference OE/OEM 121000123
- Head gasket — CMPO GSKH024: ZS158FMI-B head gasket; EAN 5057645173366; reference OE/OEM 149900075
- Base gasket — CMPO GSKB012: 156FMI(OHC) / ZS158FMI-B base gasket; EAN 5057645173304; reference OE/OEM 149900065
- Piston-pin clips — CMPO GPCLP012: Wrist-pin clips for KS125-24; EAN 5057645142355; reference OE/OEM 121000124
- Engine-family wrist pin — CMPO GDP028: 14 mm gudgeon pin, 42 x 14 x 10 mm; EAN 5057645233787; reference OE/OEM 121000155. Check against the supplied piston before fitting.
The supplied kit is unbranded aftermarket. CMPO part numbers, EANs and reference/OE numbers are included for identification and interchange checking only; they are not being presented as the manufacturer part number of the supplied kit.
Fitment
For KS125-24 engines that use the 58 mm PIST037 / PSTR032 piston-ring family. CMPO also lists a separate 56.5 mm piston kit for some KS125-24 applications, so the original piston/cylinder size must be checked before ordering.
Important Compatibility Checks Before Ordering
- Measure the original piston and cylinder before ordering; this listing is for the 58 mm replacement family
- For XTR S KS125-24, do not assume all engines use the same piston size — a separate 56.5 mm option is also documented
- Compare piston crown shape, skirt profile, pin position and ring-groove layout with the photographs
- Confirm the wrist-pin diameter and length match the piston/connecting-rod arrangement
- Compare the cylinder-head and base-gasket bore openings, stud holes and oil passages
- Check the engine code stamped on the crankcase wherever possible
Installation Notes
Top-end engine work should be completed using the correct workshop procedure. Check ring orientation and end gaps, lubricate the piston and cylinder before assembly, fit both circlips securely with their gaps correctly positioned, and ensure the piston is installed in the correct direction. Tighten cylinder-head fasteners in sequence to the engine manufacturer's specification and re-check valve clearances and cam timing after assembly.
What Is Included
One piston rebuild kit containing the piston, piston-ring set, wrist pin, two retaining clips, cylinder-head gasket and cylinder-base gasket shown in the product photographs. Cylinder barrel, cylinder head, valves, camshaft, cam chain and engine fasteners are not included.
Delivery & Returns
- Free UK delivery with an estimated 2–3 working-day service
- 30-day returns, subject to the item being returned in its original condition