Suzuki JR50 41mm Cylinder & Piston Top-End Kit
Aftermarket 41 mm standard-bore cylinder and piston kit for Suzuki JR50 two-stroke mini motorcycles using the same core 50cc cylinder / piston family.
Technical Specification
- Engine type: Air-cooled 2-stroke single cylinder
- Nominal capacity: 49cc / 50cc class
- Standard bore: 41.00 mm
- Stroke: 37.80 mm
- Standard piston-pin diameter: 12 mm
- Approx. piston-pin overall length for this family: 33.7 mm
- Typical OEM-style compression ratio: 5.6:1
- Condition: Brand new aftermarket replacement
Suzuki OEM / Search Cross-References
- Cylinder / barrel family: 11210-04012-0F0 (supersedes earlier 11210-04010 / 11210-04011-0F0 on documented applications)
- Cylinder head family: 11111-04001
- Standard piston family: 12110-43000
- Head gasket: 11141-04000
- Base gasket family: 11241-04010
These Suzuki numbers are supplied for comparison and search purposes only. This item is aftermarket / unbranded and is not represented as a Genuine Suzuki component.
What This Kit Is For
This top-end replacement is intended for rebuilding a worn, scored or damaged 50cc two-stroke cylinder assembly. Typical reasons for replacement include low compression, piston seizure, cylinder scoring, damaged piston skirts or ring lands, and restoration of an engine that has been stored or run with inadequate lubrication.
Important Package-Contents Note
The source listing positively identifies a cylinder / barrel and piston. Depending on the exact stock batch, related 41mm kits are also sold with rings, pin, circlips, small-end bearing, gaskets, studs, nuts, cylinder head and spark plug. Use the listing photographs as the final guide to the exact components supplied with SKU 01013-ENG. Do not assume unpictured parts are included.
Important Fitment Checks
- Confirm the replacement is the standard 41.00 mm bore, not an oversize or big-bore kit.
- Compare the cylinder casting, intake / transfer-port layout, exhaust-port position and mounting-stud pattern.
- Check piston crown, skirt and ring arrangement against the original engine.
- Compare the cylinder-head sealing surface and gasket pattern.
- Vacuum-petcock warning: some aftermarket versions of this cylinder family omit the vacuum take-off near the intake used on certain LT50 setups. Compare your original cylinder and the product photographs before ordering.
- If the machine has previously been rebored or modified, model/year alone is not sufficient to confirm fitment.
Installation Guidance
Correct two-stroke top-end assembly is essential. Check bore condition, piston-to-cylinder clearance, ring end gap, ring orientation, piston direction, small-end bearing, gasket condition and cylinder-head sealing before assembly. Lubricate the piston / bore during assembly and confirm the two-stroke oiling system is functioning correctly before running the engine.
After installation, rotate the engine by hand to confirm free movement and follow an appropriate running-in procedure. Professional installation is recommended if you are not experienced with two-stroke engine rebuilding.
Documented Fitment
- Suzuki JR50 - strong aftermarket fitment evidence for 1985-2006
- 41.00 mm standard-bore 49cc top-end family
- Cylinder-head reference 11111-04001 is documented on later JR50 OEM applications
Fitment note: JR50 cylinder part-number revisions exist across production. This listing is based on the widely sold 41mm replacement top-end family; compare the original cylinder, ports and head/gasket pattern before fitting.