SKF Fork Oil Seal 41x54x9 mm for HONDA CRF 250, XL 600, XR 350, KAWASAKI KDX 125 and YAMAHA TT 350 1983-2025

The SKF 41x54x9 mm OSB-41S fork oil seal is designed for HONDA CRF 250, XL 600, XR 350, YAMAHA TT 350 and KAWASAKI KDX 125 from 1983 to 2025. The fork oil seal keeps the oil inside the fork leg while letting the inner tube slide. It is a wear item: dust, mud and impacts on the tubes eventually damage its lip, and the fork leaks.

Specifications

• Brand: SKF
• Manufacturer part number: OSB-41S
• EAN code: 8050040143641
• Weight: 30 g

When to replace it?

• Film of oil on the inner tube after a few fork strokes.
• Oil traces on the fork leg, the caliper or the brake disc.
• Fork that becomes softer on one side.

Before replacing a leaking seal, clean under its lip: a trapped grain of sand is sometimes enough to cause the leak. If it still leaks, replace the seals on both legs. Measure your seal (inside diameter, outside diameter and height) or check the original part number: the size is in the name.

Fitting tips

1. Drain and disassemble the fork leg following the manual, then remove the dust seal, the circlip and the old seal.
2. Check the fork bushings and the condition of the inner tube: a scratch or a rust spot will cut a new seal.
3. Protect the end of the tube (plastic bag), oil the lip and drive the seal in straight with a seal driver of the right diameter.
4. Refit the circlip and a new dust seal, then reset the fork oil level.

Why SKF?

SKF is renowned for its fork seals, among the most durable in motocross according to the American magazine Motocross Action, which notes that the WP forks on KTMs are fitted with them as original equipment. In its Dual Compound range, the brand combines two rubber compounds moulded together: a tough green dust wiper and a softer red sealing lip, both reinforced by a metal insert.

Spare parts and items to plan

• Fork dust seals : ATHENA P40FORK455209 · ATHENA P40FORK455096
• Fork oil : LIQUI MOLY 10W 500 ml
• Fork bushings : SHOWA · INNTECK

Frequently asked questions

Do I have to change both seals?
Yes: they have the same age and the same mileage. Replace both oil seals and, ideally, both dust seals.

Why is my new seal leaking?
Most often because of a scratched or pitted tube, a lip turned back during installation, or worn bushings that let the tube develop play.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
HONDA CRF 250 2025
HONDA CRF 250 2024
HONDA CRF 250 2023
HONDA CRF 250 2022
HONDA CRF 250 2021
HONDA CRF 250 2020
HONDA CRF 250 2019
HONDA XL 600 1987
HONDA XL 600 1986
HONDA XL 600 1985
HONDA XR 350 1985
HONDA XR 350 1984
HONDA XR 350 1983
KAWASAKI KDX 125 1999
KAWASAKI KDX 125 1998
KAWASAKI KDX 125 1997
KAWASAKI KDX 125 1996
KAWASAKI KDX 125 1995
KAWASAKI KDX 125 1994
KAWASAKI KDX 125 1993
KAWASAKI KDX 125 1992
KAWASAKI KDX 125 1991
YAMAHA TT 350 1987
YAMAHA TT 350 1986