How To Avoid Leaking Motorcycle Fork Seals

Your motorcycle fork seals are leaking. Very annoying! You can finish your ride but the performance of the fork is limited and you have to get it done asap.

All fork seals leak for a reason. The main reasons for leaking seals are that the surface is not smooth or the bushes are worn. Looking after your seals can make your seals last much longer.

The surface is not smooth

Seals are designed to run on a very smooth surface. On your dirt bike suspension it is usually a chrome surface or similar. Fork and shock shafts can be damaged

  • from rocks that are not polite enough to move when you ride past them
  • from rocks that are thrown up from the front wheel, hit the engine guard and bounce back into the unprotected side of the chrome inner tube
  • from rubbing against other bikes on trailers
  • from crashes
  • from roost
  • from mud that dries on the fork tubes and creates a type of grinding paste
  • from sand and mud in combination

If you have a seal leak, make sure you carefully inspect the chrome surfaces and use your finger nail to try detecting any damage, even tiny scratches. If you can feel any high spot that catch your nail then use a nail file to flatten them carefully on the chrome tube. Small hollows are not a problem only the high spots destroy seals. File the high spot until your nail runs smoothly over the damage.

The best you can do after a muddy ride is to pull down the dust seal and clean inside of it and clean the area outside the oil seal. Put some grease between the dust seal and oil seal and push the dust seal back into place. (To read more on fork seal maintenance click here)

Bushes are worn

Seals are also designed to work within certain tolerances and excessive lateral movement due to fork bush wear is not desirable. Worn bushes with extra tolerance can cause leaking and often cause excessive air build up in the forks. (To read more about air bleeders click here)

If seals leak and no damage is found on the chrome surfaces then you should change fork bushes and the dust seals. Always use genuine seals and not aftermarket ones. They often have bad tolerances and you will have the same problem as before.

Change bushes and oil seals every 50 hrs and make sure your dust seal is in good condition and lubricate it often especially after cleaning the bike.


Here is a little table of potential trouble for your motorcycle fork seals and how to fix it.

Minimizing leaking motorcycle fork seals also depends on looking after your suspension and inspecting it often. I am sure that if you maintain your fork as mentioned above you will have good suspension, fewer leaks and you will save some money in the long run.

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