Hi!

To begin the story I've sold my YZ last year and bought a '02 Ktm 125 SX. The bike is almost perfect now. New piston, rod, bearings, tires, brake pads everything. Just got my suspension back from a local shop. I told them to set it up for mx riding and for my 150lbs weight. Having ridden 2 hours since then, the front and the back still seems to be harsh. Compression clickers are all the way out. Rebound is like half way in both for forks and shock. I think the springs are stock so they should be good for my weight. Oil is 5w. Oil height must be right, cause the forks move on the full length of the stroke. I get a lot of headshake, and the rear end is bouncing like hell too. Not to mention the armpump I get after 2 minutes.
The whole setup is close to stock values now I think.

Do you guys know any solution to make this WP stuff work better?

Cheers.

I'm no pro so take this for what its worth....

I had the same problem with my 03.  I am the third owner of the bike and it had ADR Racing stickers on the suspension.  Way too stiff for my type of riding, enough so it made it no fun to ride.  I called the number on the sticker and the guy gave me some tips and advice.  He said that if the clickers are all the way out it is the same as all the way in.  In either position they do nothing.  He said to set them all out all the way then set all to six clicks in. I think ktm is 1/2 clicks on them so 12 clicks = six full "clicks".  He also mentioned that they should be balanced as far as comp and damp as well as from front to fear.

I could not believe the difference it made for me.  Like i said i really dont know suspension very well, and do not race so my expectations might be different than yours.  Hope this helps....and if i'm spewing bs please feel free to correct me as i am trying to learn.  Good luck!

Thanks for the advice. To tell you the truth, I started adjusting the compression clickers from fully closed and adjusted it every lap so now it's fully open. I believe my problem is in the valving. I'll tear the forks apart this weekend and measure the shims.

I took the forks apart, these are the actual shim stacks:

Base valve:

8x24x0.4 This is the checkplate if I'm not mistaken.
PISTON
6x24x0.2
6x24x0.2
6x22x0.2
6x18x0.1
6x14x0.1
6x11x0.2
6x18x0.2



Mid valve:

8x24x0.1
8x24x0.1
8x24x0.1


Rebound:

two delta shims (the ones that look like a rounded triangular)
6x14x0.1
6x20x0.1
6x18x0.1
6x16x0.1 (might be 0.15)
6x14x0.1
6x14x0.1
6x10x0.3
6x16x0.1 (might be 0.15)

Edited by TommyZ, 04 June 2012 - 10:46 AM.

my 2002 ktm 125sx does that too, ive messed around with the clickers, rebuilt the shock and the forks, and it still does it, its been set up good and everything, i dont know what to do, thinking of buying a steering stabilizer before i race red bud, what do you think?

The stabilizer might help with the headshake problem but it won't really have any effect on how your forks work. On these KTM-s you can adjust the handlebar stops the reduce the steering angle so that your handlebar wont be able to flap around that much. The only downside of this is cannot be felt much on a motocross track. When doing a literally slow turn the turn radius will be a bit bigger if you limit the handlebar movement but thats all. I've read somewhere that Dean Wilson is running these adjusters outdoors and his rear wheel is set back in position fully so that the bikse becomes more stable. I think he has a steep steering angle which the mechanics were trying to compensate.

So I'd say if you have the time and patience you should look into your forks and see whats there. You can mess a lot with the BV and MV stack. When stock these WP forks only have a single stage stack on the basevalve that is stiff and a midvalve that doesnt have any tapered stacks. It has a float level and shims arent bending when oil is flowing through the piston. From what I understand the midvalve comes into effect when a bigger pressure builds up in your forks so it affects high speed damping. A lot of people change this midvalve to a tapered stack with reduced or zero float. Here are some interesting topics to read:

http://www.dirtrider...69&page=1&pp=10
http://www.dirtbikew...hp/t-33585.html

I took the forks apart and I'm messing with the base valve. If that doesnt work I will change the mid valve to a tepered stack and see how it goes. I just don't want to order shims if I don't need.

Edited by TommyZ, 09 June 2012 - 10:10 PM.

TommyZ, on 09 June 2012 - 09:54 PM, said:

You are incorrect about what the midvalve does.  The midvalve sits opposite the rebound stack and is impacted by the R clicker setting as well.  The midvalve controls the low speed shaft movements (trail trash), the compression handles the high speed shaft movements (that one big arse root in the trail).  So, you can soften up the forks compression feeling by going out on the rebound clicker, within reason.  

The magic is in the midvalve, though you can make the forks feel a little better with some base valve changes.  If you make multiple changes at one time, you won't know what is affecting what.  So, have plenty of fork oil and a good work bench, along with plenty of time!

Also, running the clickers all the way out is just bypassing the valving for the most part.  You actually end up with a harsher ride because when the pressure builds enough to make the valve stack move, you get a harshness just like smacking water with a flat hand.  It doesn't disperse smoothly.  The more fluid you can force thru the valving, the more control you will have controlling the bike.  

with a revalve, I run my forks at 15/15, shock at 14/17.

I have been down this road and it can make your head spin.  It is messy work and not simple to make changes.  I finally said to heck with it and let a pro do it.  Much happier just riding now.

Edited by gmoss357, 10 June 2012 - 12:31 PM.

Thanks for clearing that up!

I was about to assemble the forks again but wanted to check the other fork if it has the same shims. (Forks were sent to a suspension guy to oil change seal change and revalving for my weight.)
Look whats wrong:

Hahaha, seen that type of thing before.  That is what happens when you let yourself get disturbed when doing valving.  I was there with my tuner this past weekend when he essentially revalved my BV.  He laid out both stacks like you have, then assembled.  Then, there is no question you have it correct.  If you do one, put it together, start on the other, get a call, or some other distraction, then come back, that is what can happen.

We are all human and mistakes with valving is easy to do if you are not totally focused.  I misplaced a couple shims when I was doing my own stuff, trying to learn, and realized right quick how easy it is to make a mistake when distractions are near.

Edited by gmoss357, 14 June 2012 - 01:02 PM.

Im fairly sure i removed 2 shims on my 03.

Im fairly sure i removed 2 shims on my 03.

I don't know whoever made that valving job before must have been a previous owner but this made me realize that the guy who I sent the forks (and shock too) didn't take the BV apart. There was a broken shim clogged in one of the piston holes. I was so pissed off I forgot to take a pic about this. I had the camera at hand...

As for the stack I rearranged the shims "equally" on both sides and made a 2 stage stack by putting a smaller shim after the 3rd or 4th big one. Forgot to take photos about that.

I've ridden the bike an hour or so and I can tell you the forks feel much better now. Still getting a little headshake but that seems to eliminate after lowering the air pressure in the tires. Now I'm messing with the clickers trying to set the thing up. I'll post a slow-motion video to let you see the forks working. But thats for later cause its 4 AM here. I woke up halfly and felt an itch in my nose and yeah blood all over the stuff LOL. Sorry if that sounded disturbing. I don't know why am I thinking about suspension in these situations but I had to turn on the laptop and write this here.

So here it is. I swear the quality wasn't that bad before uploading.

Edited by TommyZ, 15 June 2012 - 02:43 AM.

With the headshake, tighten down the the head tube bearings to the point the bars just ease to the stop when leaned on the stand.  The tapered bearings need some load on them.  I had some headshake as well, didn't realize this till my tuner was going over the bike with me.  Really calmed the bike down.  Otherwise, look at the rear sag, that can cause headshake as well if it is off.

Thank you for the help, again
I will tighten those bearings and measure the sag. The forks are flat with the clamps anyways. I couldn't raise the front end more by adjusting that. But an incorrect sag can f*ck up the whole geometry thats true.

I run my forks on the 2nd line without issue now.  I had issue either way before.

Thats good to hear! If the headshake goes away I will definitely raise the forks to make the bike turn even quicker.

Wow! I've tightened those head tube bearings. Huge improvement! I'm able to ride 15-20 minutes again like I used to. I still get some bar twitching on bigger whoops but only one or two at the time, so it's not shaking that bad.
The other good effect I feel is when cornering. I'm able to lean the bike more cause the tightened bearings now help to keep the handlebar almost straight and I think it reduces the counter steering effect, so if I lean the bike over it just stays there and thats good. Though I had to take care on flat turns to avoid front wheel slide out.

Now I'm happy with the handling overall and I enjoy riding. Again. Thank you for the advices!