Fork rebound adjuster.

13 replies to this topic
  • Mr-Xr70

Posted October 26, 2008 - 01:00 AM


I went to adjust the rebound on my 06 250sx fork and the right leg has gone so stiff i can hardly turn it. I removed the hand adjustment but it was not seized. I then tried turning it with a screw driver and it was still extremely stiff and it does not click. Is this a common problem? How do i fix it?

  • gmoss357

Posted October 26, 2008 - 06:31 AM


has the fork been apart lately?

  • krazyinski

Posted October 26, 2008 - 03:26 PM


yes The word I got from My race tech guy was WP stuff is bad about the needle sticking, he gave me the settings for mine from all the way out and suggested not to turn it all the way in till it seats.

  • Supertrunk

Posted October 26, 2008 - 05:14 PM


That's pretty much BS, KTM is not "bad" about this at all.....................
Are you talking about the black plastic rebound adjuster knob on top of your forks?. It's two piece, with the upper knob retained by two balls and a spring (the "clicker" part) and a lower black plastic threaded piece that travels up and down a threaded passage in the fork cap?

The only way to know where you are and to set either clicker needle consistantly is to bottom it and count clicks out from full closed. Other wise you are comparing "fence posts to clouds", not "apples to apples"............

Posted Image

If the lower piece was removed and cross threaded upon reassembly, that could happen. The lower black plastic piece may need to be replaced to fix this correctly. If the rebound rod was screwed into the cap without the sealing o-ring and over-tightened it could roll the threads into the passage requiring the passage to be cleaned up with a tap.

What does happen to KTMs a lot is the owner does not do full disassemblies to clean all the parts with an oil change and the needle itself gets gummed up.

Posted Image

Here is what a clean assembly would look like.

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Your rebound needle opens and closes the bypass hole (labeled in red here) when you turn the adjuster knob. If you are not fully seated to begin with, you will have no way of knowing how much needle is blocking the passage from fork to fork (kinda' like clip position on a carb needle).

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This is a good look at what is inside your fork..........................( )

  • Mr-Xr70

Posted October 26, 2008 - 09:50 PM


Thanks Supertrunk for the quality info. It's the second part of the adjuster that is super stiff. I will try and take it all the way out so i can have a look at it. The forks have never been apart, the bike has not done much work. The original front tyre is still in good condition.
Will i have to remove all oil from the forks to get to the rebound valve?

  • Supertrunk

Posted October 27, 2008 - 01:45 AM


I would check one thing at a time.
If the rebound adjuster is stiff, just pull the cap. It just sounds like the lower adjuster is dirty and frozen in the cap. A dirty needle shouldn't make the adjuster hard to turn.

Best bet is to follow the link over to the "pinned" front fork components thread that I posted at the bottom of the pictures.

When you get there, scroll down to the post, "Help! My Rebound Adjuster Just Spins and Spins", there's everything you need to know on hw to pull your fork caps and replace them correctly.

  • Mr-Xr70

Posted October 27, 2008 - 01:51 AM


Well my adjuster started to just spin. So i pulled the cap off and inspected the lower part of the adjuster. The thread on it is pretty much stuffed and it looks pretty ugly. The long rod doesn't stick out like i have seen in the other photo's. It sits flush with the top of the rod. Is this normal? Does that mean my rebound spring could be stuck down?

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  • krazyinski

Posted October 27, 2008 - 03:18 AM


"What does happen to KTMs a lot is the owner does not do full disassemblies to clean all the parts with an oil change and the needle itself gets gummed up."

maybe this is the sticking needle thing?

so your saying that this is BS? no wait you said this !! just ribbin ya !!!

I am not a stickler for details, I like to ride and let those that like to be professionals or try to be, stick to the details.

I like the fact that my tuner's advise works for me this is what I pay for .

Its just great that you seam to be!

  • Mike in Fresno

Posted October 27, 2008 - 07:48 AM


well i dont know what it is that is wrong, but yes if the lomg rod or tube is not sticking up then something is wrong

  • Mr-Xr70

Posted October 27, 2008 - 01:48 PM


Stripped my fork down today, finally got the rebound tap out. That was a mission, it's so tight. Then i spotted the problem, the needle was stuck hard down. It was also kinda dirty and sticky. So i gave it all a good clean and put a few drops of oil on it so hopefully it doesn't happen again.
I pulled the rebound shim stack apart and kept everything in order. I'm just not sure where the two non round shims should sit over the valve, do they sit one on top of each other covering the valve hole?

  • oldgeezer91

Posted February 06, 2010 - 09:57 AM


My rebound adjusters both appear to be "frozen".
I don't want to sound stupid, but do I just remove the fork caps to clean everything up, or do I have to remove the forks and do a full disassembly?

  • gmoss357

Posted February 06, 2010 - 12:10 PM


If you don't know what you are doing, you can really mess up these forks. there are subassemblies that have to be put together in a certain order for everything to go together correctly.

as far as the inner rod not sticking up, the black guide has to screw down on the rod and seat itself, then the cap screws onto the rod, bottoms in the cap, then that whole assembly screws down to meet the spring guide. The rod inside that rod has to seat on the rebound needle, the one that sticks onto the rebound adjuster in the cap.

Did you remove the peening from the rebound stack before pulling the shims?

The Deltas, or triangular shims seat against the piston and cover the holes. they must be kept straight. then, on the midvalve side you have some 8mm ID shims that have to clear the lip on the rebound tap when you put it back together.

I got tired of messing with these trying to valve them myself, so I just take them to to my tuner once a year. It definitely can try one's patience...

  • oldgeezer91

Posted February 06, 2010 - 12:46 PM


I didn't take anything apart, yet. It seemed like I could examine the basic problem by just taking off the caps. If I had to go any farther than that, it's beyond my pay grade of volunteer mechanic!

  • gmoss357

Posted February 06, 2010 - 01:03 PM


I didn't take anything apart, yet. It seemed like I could examine the basic problem by just taking off the caps. If I had to go any farther than that, it's beyond my pay grade of volunteer mechanic!

did you pull the caps off the inner rod? if so, there is a process to getting it back together right. not a big deal, but you want to make sure it goes together correctly. you are also supposed to seat the bottom part of the cap with the male end of the rebound adjuster, up into the cap before reassembly.


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