450 KYB SSS Fork Leak/Fluid level question



11 replies to this topic
  • Yamaha211

Posted November 04, 2015 - 05:28 PM

#1

I just picked up a 2009 YZ450f with a couple issues that I've been working on in my spare time and I'm a little out of my field of experience when it comes to fork setup on a dirt bike. I grew up on quads so I'm familiar with all of settings and what not and getting them dialed where I want but I've never messed with fork oil levels or in this case, a fork oil leak. 

 

The right side fork stanchion is leaking oil from the very bottom where the compression dampener bolt is. I looked up the exploded view and noted that there are a series of washers and seals that seal that bottom bolt from leaking oil and I have ordered them and have them. I should I be able to just pull the bottom bolt, drain the fluid, and replace the washer and seal right?

 

Then I also ordered a tool to measure fork fluid with the syringe to set my fork fluid levels once I've replaced the seal. It has metric measurements on it so my question is what measurement should I be using to get the correct cc of fork oil in my fork? Is there anything else that I need to worry about when I am going to be pulling that bottom bolt out and draining all the oil out other than just refilling the fork oil at the top of the fork when I'm done to the correct level? 

 

Any help is much appreciated, Thanks.

 



  • bk29

Posted November 04, 2015 - 05:53 PM

#2

Do you have the Yamaha manual for your bike? It's going to be a little harder than you think but it's definitely doable if you have the book. Any Yamaha manual for a bike with the sss fork is better than nothing.

  • Yamaha211

Posted November 04, 2015 - 06:00 PM

#3

I've got the .pdf version on my computer and I've printed off the whole section about the forks, the only problem is it doesn't specify the procedure for just replacing that bolt and what I should need to do to get my fork set up and good to go after doing so. It has the whole procedure for tear down/reassembly so I'll read through it tonight and see if I can figure out what I need to do and what I don't need to do.



  • bk29

Posted November 04, 2015 - 06:58 PM

#4

After you back the bolt at the bottom you will have to compress the spring to get it out of the tube so you can remove it from the cartridge. There is a tool you put in the cartridge shaft to hold it out so you can work on it. I think you could use a crescent wrench for this but I'm not sure. I'm not sure how you would set your oil level accurately with out removing the cartridge from the outer tube and making sure you have all of the old oil out. If you think you haven't lost a significant amount of oil, you could keep the fork inverted and not change the oil level. You don't need to go into the inner oil chamber or separate the tubes. If you're willing to tackle this project, it's probably a good idea to buy all of the tools you need to do a seal and oil change. Leaking forks are a part of riding dirt bikes, it's nice to have everything thing to handle it when it comes up.

  • bk29

Posted November 04, 2015 - 07:02 PM

#5

I meant to say "a tool you put ON the cartridge shaft"

  • Dklassen

Posted November 04, 2015 - 09:38 PM

#6

I just picked up a 2009 YZ450f with a couple issues that I've been working on in my spare time and I'm a little out of my field of experience when it comes to fork setup on a dirt bike. I grew up on quads so I'm familiar with all of settings and what not and getting them dialed where I want but I've never messed with fork oil levels or in this case, a fork oil leak.

The right side fork stanchion is leaking oil from the very bottom where the compression dampener bolt is. I looked up the exploded view and noted that there are a series of washers and seals that seal that bottom bolt from leaking oil and I have ordered them and have them. I should I be able to just pull the bottom bolt, drain the fluid, and replace the washer and seal right?

Then I also ordered a tool to measure fork fluid with the syringe to set my fork fluid levels once I've replaced the seal. It has metric measurements on it so my question is what measurement should I be using to get the correct cc of fork oil in my fork? Is there anything else that I need to worry about when I am going to be pulling that bottom bolt out and draining all the oil out other than just refilling the fork oil at the top of the fork when I'm done to the correct level?

Any help is much appreciated, Thanks.

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  • grayracer513

Posted November 05, 2015 - 07:41 AM

#7

There are two separate oil supplies in the SSS fork, one is the inner chamber, or cartridge, which is filled full and bled free of air, and the other is the outer chamber.  The leveling syringe you bought is not used for this fork.  Outer chamber oil is filled by volume, not level.  Baseline is 350cc, but I personally like a lower level (325cc).

 

IF the only thing you are looking to do is reseal the comp adjuster, start by counting down the clicks as you run the adjuster all the way down.  Record that number so you can reset it.  Then back the adjuster out until it stops.

 

Loosen the adjuster and back it out.  Drain the oil.  Stand the fork on its top, compress it slightly to allow you to place the damper rod holder shown in the manual under the lock nut.  Loosen the nut, remove the adjuster and make your repairs.

 

The manual will make an obscure reference to a gap between the nut and adjuster as you assemble it.  To clear things up, read this:

 

http://www.thumperta...k/#entry6860151

 

To do a full oil change, read this:

 

http://www.thumperta...-2#entry7613090



  • Yamaha211

Posted November 05, 2015 - 08:18 AM

#8

Thanks for all of the helpful advice, right now from the information that I've gathered I think I'm going to check the bolt and make sure it's torqued to spec (40 ft lbs) and clean it all up again and see if that fixes it. I know that I've read multiple times that these shocks are very sensitive to oil quantity changes, I don't know exactly how much oil it has lost but it was enough to give the wheel spokes a decent coat for a couple inches around the bottom of the fork where it was leaking and rode by the person I bought it from. He told me he didn't notice it was leaking until the last time that he rode it and it's been sitting since then. I cleaned the bike and noticed it still has a very slow oil leak from the bottom bolt on the fork but just barely enough to feel with my finger. If I torque it to spec and it stops should I be able to ride it until I have the time to rebuild the whole thing? That's why I inquired about checking the oil level, ideally, I would torque the bolt, it would seal, I would check the oil level and add some if needed and ride it that way until a couple weeks down the road once it's really cold and I wanna do a full rebuild on my forks.


Edited by Yamaha211, November 05, 2015 - 08:20 AM.


  • grayracer513

Posted November 05, 2015 - 09:05 AM

#9

Be sure the leak is really coming from the adjuster assembly.  They very rarely leak.  What happens more often is that a leak develops between the aluminum axle lug and the inner tube, which is a job for a suspension shop to repair. 

 

There is no means of checking the oil level of an assembled SSS fork apart from draining and refilling.



  • Yamaha211

Posted November 05, 2015 - 01:29 PM

#10

Alright, I'll torque the adjuster assembly to spec and check it. Where is the origin of the leak that you're referring to between the aluminum axle lug and the inner tube? I'm looking at the owners manual at the exploded view of the fork is there any way you can reference that image or maybe a picture that shows me where it could potentially be leaking?

  • grayracer513

Posted November 05, 2015 - 01:42 PM

#11

The axle lug is threaded onto the bottom of the steel fork inner tube, or stanchion, then locked in place with a large set screw and a sealant. The leak I mentioned develops between the two parts.

  • Yamaha211

Posted November 05, 2015 - 03:30 PM

#12

The axle lug is threaded onto the bottom of the steel fork inner tube, or stanchion, then locked in place with a large set screw and a sealant. The leak I mentioned develops between the two parts.

 

Alright, I see what you're referring to. Thanks for the info grayracer513, I appreciate it. Everyone on here has been extremely helpful. As far as the owner's manual goes they don't actually have a procedure for removing the axle lug or servicing it, the more that I've read up on it it seems that it isn't supposed to ever come off but it's a fairly common issue for a leak to develop there. Any idea what my local suspension shop should charge me to fix that leak? and then, seperately, what is average cost for them to do a rebuild on my forks and set them up for my weight? If I'm going to tear them off and have them service them I might as well go all out if they're off. 

 

As far as the rear shock goes I could just get it re sprung for my weight or will they also mess with the valving as well if I take it in? There's a suspension shop local to me that's highly recommend by lots of buddies called Fineline Suspension.

 

What you guys are paying will be useful information to me for shock/fork re-valve, full fork rebuild, axle lug leak repair, etc. so that I can compare their price that they quote me for reasonability


Edited by Yamaha211, November 05, 2015 - 04:14 PM.






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