Maintenance Tips - Fork Seals

Lexi Pechout and Danika White are in the shop with SurfinBerms to walk you through how to change your fork seals on a dirtbike. 

There’s nothing worse than going to load up your bike for your next ride, and find oil leaking out of your front forks! No worries though, because it’s actually not that bad of a job. You just need a few tools and a clean work space.

This process is very close to the same on most forks, in the maintenance video we are working with forks off a 2019 KTM 350 SX-F. The internal chamber and whether or not it’s a spring fork will be the key differences with other dirtbikes. These are the WP AER Forks, which are on many KTM, Husqvarna and GasGas Models 2016 and up. The AER Fork uses air pressure as it’s “spring support”.

What You Will Need


1. New Fork Seals – If your Forks haven’t been serviced for a while we recommend getting new bushings as well. On the WP Forks we recommend getting the full Power Parts Fork Service Kit as it comes with everything you need.
2. Fork Oil – Make sure to check your manual for the proper weight oil and amount.
3. Seal Driver – We really like the DRC Fork Seal Driver Kit, since its priced well and if you have multiple bikes it comes with different size driver attachments.
4. Fork Cap Wrench – we use the Motion Pro Fork Cap Wrench.
5. Vice – make sure your vice has soft jaws or else it will damage the forks.
6. Ratchet with correct size socket – on the 19 KTM AER Forks you’d need a 19mm socket.
7. Small Flat Head Screwdriver.
8. Oil Drain Container – this is the Matrix Concepts Oil Drain Container.
9. Oil Measuring Cup – we use the Ratio Rite Measuring Cup.
10. Paper Towel
11. Gloves
12. Brake Clean – always good to have on hand to clean up any oily messy during the process.


This is a moderate to advanced maintenance job that does require a couple specific tools. If you decide to tackle this job just take your time and keep track of how you lay your parts out, while keeping the area nice and clean. If you are not comfortable with this job, any Dealer or Suspension Shop will be able to get this done for you.

If you try this service, send us updates, we’d love to hear how it went and would be glad to help if you need any assistance along the way!  

Leave a comment