KTM/WP Quality control

[Greg in Oz]

OK, this is a bit of a saga but worth your time if you have a new KTM. We collected the 250SX from the dealer and were getting ready to do some front end testing, new 16mm offset triple clamps and some valving changes in the forks. So the Oz KTM race team gives us some settings and oil height changes and we're putting em in to try before Jer's gear arrives on the big bird from US. Change oil height, turn em over , rattle out base valve. File off the peening on the retainer nut and pull apart. Hmm, one of the shims is seriously graunched. That's OK there's 7 of these 24mm dia ones in the standard stack and we only need 6. Change over to the dual stage stack and button up. Same for next leg, which had felt a little stiff even after the oil height was lowered. Hmmm, few too many shims here!!! We got a double batch of 24mm shims. 14 in all!!! Now I don't know if these forks are made in pairs. I suspect not. What are the odds of getting 2 dud units in the kind of production runs KTM do ending up in the same bike unless WP's quality control really sucks? So the moral here is pull the forks apart and check em, and if they're duds hit your dealer. Guess who's rebuilding the shock next week!!!
BTW standard settings are 7x 24/.1, 22/.1, 20/.1, 18/.1,16/.1, 14/.1, 11/.1, 18/.1.
If they feel a little harsh, take out one of the 24s, and put a 12/.15 crossover between the 5th and 6th 24s. Lower oil height from 100 to 150 mm.
Thanks to your magazines thinking all riding happens on supercross tracks, they went to a single stage damping stack.

 

[marcusgunby]

Ive heard of alot of forks coming from WP with incorrect shim stacks-it must be hard to to get right number of shimes when they love to stick together.The japs are better because they have smaller fingers:debil:

 

[shockdoc]

I've also seen a lot of 43mm WP forks that have the rebound pistons loose from the factory. I always check them while servicing.

This same thing is happening on the new '02 CR250. I have seen and heard of approx 20-25 new CR's with little to no time on them and the rebound pistons loose.


doc

 

[kenkfish]

I am curious if the 16mm clamps wil fit with out hitting the pipe when suspension collapses. I have the new 250 as well, and swear that the clearance with the 18's and stock pipe is close. Please keep us posted on any other mods.

Ken

 

[Greg in Oz]

Dunno about standard or other brands but 16 offset works with the KTM Doma pipe.

 

[Strick]

Greg, Jeremy, Marcus.....

Where can I get this shim? I am going to change the fork oil after Sunday's (final) race. I race and ride desert. Is this shim change and lowering of the fork oil a must for me in terms of my type of riding/racing? I would think the answer is yes. Thanks for any input.

 

[Greg in Oz]

Strick,
I believe the crossover shim I mentioned is a KTM part. I don't have the book at hand but I got the shims from the KTM importer here in Oz. Any suspension shop that does WP should have some. They're 6mm ID.

 

[Bud-Man]

Strick,
The 12.15 shim is a common crossover shim in the stock EXC/MXC valve stack. You should be able to order it from a KTM dealer. However any suspension shop that works on WP or Showa forks should have this shim. (The WP and Showa forks use the same size i.d. shims.) Cost should be about a buck and you may even be able to weasle a couple from someone :) .

 

[Strick]

O.K. race season is officially over for me. So, the forks are off, and since I have never wandered past changing the springs, and the oil, I am going down to a local bike shop. We have a race tech certified shop here in town, and the owner is a friend of mine. He and I are going to have a little KTM quality control inspection on the 48mms tomorrow! I have already discovered one thing pretty strange. The left fork is much stiffer (when pushing down) than the right spring. I have never found that to be the case in the other forks I have serviced???

I'll post back my findings tomorrow.

Thanks again for all the insight and advice guys:D

 

[Strick]

Update. The shim stack in mine was also incorrect. One side had 8 -24/.1, the other had 7 -24/.1 I removed the extra then removed one more from each side for plushness (desert racing), and added the smaller 12/.15 between 5 and 6. I also lowered the oil height to 150, and used 5wt. fork oil. I hope it all works the way I am hoping it will:D

 

[DEGBERT]

In my 99 300EXC, one fork had a single stage stack and the other had a duel stage stack. I guess I got one MX fork and one offroad fork. I little advice about revalving the WP forks, you can revalve the passive stack until your blue in the face, but until you change the active valving (mid valve) you will never get the results you want.

 

[MACE]

Originally posted by marcusgunby
Ive heard of alot of forks coming from WP with incorrect shim stacks-it must be hard to to get right number of shimes when they love to stick together.The japs are better because they have smaller fingers:debil:

It's hard to count when you are seeing double from the beer in the vending machines too. Jap forks sometimes have cigarette butts in them.

Now us rednecks are the top tuners because them pork rind remnants reduce stiction.

BTW, who says you have to have the same spec in each leg anyway? Ok I know who says, but have they ever really given any thought to WHY.

 

[Strick]

Originally posted by DEGBERT
In my 99 300EXC, one fork had a single stage stack and the other had a duel stage stack. I guess I got one MX fork and one offroad fork. I little advice about revalving the WP forks, you can revalve the passive stack until your blue in the face, but until you change the active valving (mid valve) you will never get the results you want.

Degbert, this is the first time I have delved this far into my forks, so I am experimenting as much as anything! On the '99's because of the differing fork legs, one having rebound adjustment and the other compression, could that have anything to do with the differing stacks?

Can you please define passive stack and active stack? Thanks

Be gentle I am a fork novice here;)

 

[KiwiBird]

For forks (although the shock is essentially the same)

Passive stack is the one on the base valve (it doesn't move). Oil moves through it when the the damping rod moves and the rod volume displaces oil through the base valve.

Active stack, often called the mid valve, is on the other side of the rebound stack. It is the one that moves - hence active. Oil moves through the active stack when the damping rod moves.

 

[Strick]

One word for my re-worked forks - WOW!

Greg in OZ - thank you very much for your heads up and the dual stage parameters.

Kiwi - thanks for the definitions!