02' YZ426F fork seal question

6 replies to this topic
  • sac36555

Posted October 10, 2008 - 02:59 AM


I have an 02' YZ426F and the fork seals are completely shot. I want to rebuild them myself (cost/experience). Is there any special tools I need? also, what parts do I need to buy to re-do them??? anything is helpful, especially photos.

  • matt4x4

Posted October 10, 2008 - 03:55 AM


you can buy an aftermarket kit for about 30 bucks that includes the seal and dust seal. Forgot to mention - you'll need fork oil as well.


The 02 still has the easier forks to work with - they are not a twin chamber so it's an easier process.
On youtube, there are several rockymountainmc videos that show exactly what you need to do - just make sure you get the right ones since they have one set for twin chamber and one set for the older style.

I think it can all be done without special tools - twin chambers usually require at least one special tool.

Here's a diagram of the fork:
Posted Image

  • grayracer513

Posted October 10, 2008 - 05:49 AM


Follow the procedure in the manual, but without the removal of the base valve and damper cartridge. It makes a little better job to pull all that out and clean it, but it's not necessary just to replace the seals. Once the springs are out, check the forks for looseness in the bushings. If there is excessive play, replace the bushings (items 4 and 5 in the posted drawing...the book gives them odd names).

Carefully inspect the inner tubes for scratches and burrs big enough to feel with your fingernail, and sand over them lightly with 400 grit in a cross hatch if need be.

You will need a seal driver. Some have fabbed one up from PVC, but the real thing works much better:


If you need a manual:


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  • sac36555

Posted October 10, 2008 - 10:01 PM


thanks, do you have any pics/comments showing you use the pilot driver. where do you use it exactly? and when?

  • grayracer513

Posted October 11, 2008 - 07:53 AM


The manual does. It's a split tube affair that is assembled over the inner fork tube, then used to drive the seal down against its seat. It's made for the job so it contacts the seal only where it is safe to do so.

  • mkporn

Posted October 11, 2008 - 03:37 PM


if its an 02 with lots of hours on it, you might just save yourself some time and labor in the long run by buying the complet kit, I cant remember off the top of my head, but I think it is pivot works or MSR that sells a complete kit with new bushings, seals, wipers, keepers and o-rings for about $70.....you will be suprised what it will make the front end feel like with new bushings.

  • mkporn

Posted October 11, 2008 - 03:38 PM


you can get a complete set from KnL also

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