About the Yamaha YZ125
A YZ125 application comparison that makes the fork-seal size change visible.
A YZ125 parts list can span very different machines: the featured engine gasket set lists 1977–1978, while the carburetor kit lists 1999–2015. Those ranges describe individual products. They do not group all YZ125 engines, carburetors and forks into interchangeable generations.
Compare the fork dimensions before ordering
The 1996–2003 oil-seal example measures 46 × 58 × 9.5 mm; the 2004–2011 option measures 48 × 58 × 8.5 mm. The outside diameter is the same, but the inside diameter and height differ. Check all three measurements and the profile, particularly after a front-end swap. For a different displacement, start with the Yamaha YZ family.
Model and component differencesYZ125 repair checkpoints
YZ125, 1977–1978
Vintage engine gasket set
Match the installed engine and included gasket shapes to the joints being opened. This vintage set does not establish later-engine coverage.
YZ125, 1999–2015
Carburetor rebuild kit
Record the carburetor body marking and compare included components and jet sizes. A kit application does not determine the tuning for a modified engine or exhaust.
YZ125, 1996–2003
46 × 58 × 9.5 mm fork oil seals
Compare inside diameter, outside diameter, height and profile. Identify the fork itself on a competition bike with donor suspension.
YZ125, 2004–2011
48 × 58 × 8.5 mm fork oil seals
This separate seal has a larger inside diameter and lower height than the 1996–2003 example. Do not select using the shared 58 mm outside diameter alone.
Identify your motorcycle before orderingYZ125 identification checklist
- Confirm the model year using the frame identification and matching Yamaha documentation.
- Record the engine and carburetor markings separately, including any replacement cylinder or carburetor.
- Identify the fitted fork assembly and original seal dimensions before ordering suspension service parts.
Contact PartsNMore with your model, year and clear photographs of the component and its markings.