Fork seals

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?

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

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.

Na I bought the right tools made life easy.

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?

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.

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?

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!!!

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

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

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.

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

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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