Fork seals

16 replies to this topic
  • TheUSMC1775

Posted March 06, 2015 - 12:09 PM


Hey everyone as you know fork seals come and go and I'm going to attempt on replacing them myself for the first time never done them before so I got a few questions. So I have a 2009 yz450f and i didn't get a Manuel is the suspension on my bike a kyb? And from videos I've seen this is what I got out of it, 1.count your compression clicks and rebound clicks. 2. Unscrew ur top cap. 3. Drain the oil. 4. Unscrew rebound nut. 5. Take out rebound rod. 6 remove damper and spring assembly. 7. Remove dust seal and seal clip ring. 8 seperate forks, replace seals and re assemble obvious with oil. is this right for my 2009 yz450f forks?

  • grayracer513

Posted March 06, 2015 - 01:09 PM


Counting out the compression clickers and backing them off is not required, even if you plan on changing the oil in the cartridge.  The rebound is another matter, and yes, you should find where you're currently set and then back the clickers all the way out .


Yes, they're KYB's, and yes, the procedure is correct.


Now, download a manual:


  • highdezyzf450

Posted March 06, 2015 - 07:35 PM


I did my front last weekend and my rear today and in my opinion the front was way easier. My bike is a 2010 and seriously easier then you think. I used the dyi fork video on YouTube

  • grayracer513

Posted March 07, 2015 - 10:02 AM


Ain't that tough is it?  :thumbsup:


If you did your first set with jerry-rigged or homemade tools, you should see how easy it is with the real ones.

  • highdezyzf450

Posted March 07, 2015 - 11:49 AM


Na I bought the right tools made life easy.

  • TheUSMC1775

Posted March 15, 2015 - 05:47 AM


Hey guys I just wanna add to this, I forgot to order a inner chamber cap tool , do I really need to change the fluid in the inner chamber? Or could I leave that alone?

  • grayracer513

Posted March 15, 2015 - 06:32 AM


It's a good idea to change it, particularly if you're changing brands of fork oil, but no, it's not absolutely necessary if the fork works OK.

  • TheUSMC1775

Posted March 15, 2015 - 07:14 AM


Ok so I might as well order that inner cap tool an do it right, now I don't have a Manuel is thier anyway u could help me out on what size cap tool I'll need I kno motion pro makes a cap tool for kyb would it fit on my 09?

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  • grayracer513

Posted March 15, 2015 - 09:10 AM


32mm.  Your forks ARE KYB's. 


Manuals, free:



  • TheUSMC1775

Posted March 19, 2015 - 12:50 PM


Ok even with a Manuel I'm still lost, how much fluid does my inner chamber need in CCs and OZs I just wanna get these forks done thier way over due. Please help thank you!!!

  • grayracer513

Posted March 19, 2015 - 01:16 PM


The inner chamber is not filled by volume, it is filled to excess, then assembled, then the excess oil and any included air is forced out during the bleeding process.



  • TheUSMC1775

Posted March 19, 2015 - 01:33 PM


Ok I only got one bottle of maxima fork fluid I think it's a 33 oz bottle I hope that's enough ?

  • mlatour

Posted March 19, 2015 - 01:53 PM


Outer tubes take about 350cc per leg, plus about 180 to 200cc to fill and purge each cartridge assembly

figure about 40oz required so have 2 quarts of 5W fork oil handy before starting the job.


I'd recommend taking note of all adjusters and backing them out to full 'soft' as a preventative measure as myself by coincidence or not,

have previously damaged the tip of a compression needle during re-assembly while it was still screwed in the adjusted position.

(re-installing the base valve after doing the free piston mod)


Here's a couple of very handy videos I've used to learn SSS fork servicing:


Some good tips here but this guys doesn't look to be the most meticulous in his technique.

Seal replacement shown only and not dis-assembly of the cartridge, you might as well have a look into there while you're servicing the forks.

Good tip on using the axle as a holding lever while pushing against the spring to insert the 'H' tool onto the rod.


And two videos (part 1 & 2) by TBT Racing which are very explicative,

complete dis-assembly including the cartridge, plus a how-to on the free piston mod.

Edited by mlatour, March 19, 2015 - 02:11 PM.

  • TheUSMC1775

Posted March 21, 2015 - 03:00 PM


Got both forks apart and I found out both inner valves are cracked, bottom o rings are in pieces, so I'm at a stand still till I find a shop that just sells the platic tube.

  • mlatour

Posted March 21, 2015 - 08:35 PM


The plastic free pistons are usualy not available separately from Yamaha,

they are only sold as a complete 'compression valve assembly' that includes

the whole fork cap, base valve, free piston, piston spring etc.


For your bike, it's part number : 2S2-2316A-20

and needless to say it's expensive!


Best bet is to buy new metal replacement pistons like the SDI, or find plastic ones on E-Bay.

Edited by mlatour, March 21, 2015 - 08:38 PM.

  • grayracer513

Posted March 22, 2015 - 07:41 AM


Suspension Direct sells both the OEM plastic pistons and the vented aluminum replacements.  If you choose the plastic ones, drill them as described here so they won't be so prone to fail again. 




  • jcm3

Posted March 22, 2015 - 03:22 PM


Ain't that tough is it?  :thumbsup:


If you did your first set with jerry-rigged or homemade tools, you should see how easy it is with the real ones.


If you did your first set with jerry-rigged or homemade tools, you should see how easy it is with the real ones.


Been there, done that.  The next time I need to buy the right tools as my home made pvc pipe tool I made when I did my old YZ426 forks worked, but... :facepalm:

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