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KTM SX-f WP Forks Service questions for

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I have a question about servicing my 09 KTM 250SX-f suspension.

All I want to do is change the fork oil in the inner and outer chamber.

I know you have to release the nitrogen from the chamber if you need to revalve, but what if you just want to change out the oil in the inner?

I'm familar with the precedures on Showa but this looks similar but that bladder freaks me out b/c I don't want to have to recharge it.

I'm guessing you don't need to do, and if so is it a pain to slide out the bladder?

any tips?

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Yes, you have to release the pressure before you take it apart (at least, you should) and then re-charge it upon re-assembly.

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DANG IT....

Had a feeling I had to do that.

I have read about some people using air. Can you really notice

air is 78% N.

For the rear shock def I'd use Nitrogen is it that critical in the forks.

I got craploads of Nitrogen tanks at work but I might get in trouble, LOL.

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Can you really notice

air is 78% N.

For the rear shock def I'd use Nitrogen is it that critical in the forks.

I got craploads of Nitrogen tanks at work but I might get in trouble, LOL.

Yes, and just as important is the correct gauge to measure. I had a shop do it wrong and it sucked really bad. The correct or incorrect amount of nitrogen will effect the performance. You need to have the right tools for this.

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I have a question about servicing my 09 KTM 250SX-f suspension.

All I want to do is change the fork oil in the inner and outer chamber.

I know you have to release the nitrogen from the chamber if you need to revalve, but what if you just want to change out the oil in the inner?

I'm familar with the precedures on Showa but this looks similar but that bladder freaks me out b/c I don't want to have to recharge it.

I'm guessing you don't need to do, and if so is it a pain to slide out the bladder?

any tips?

As noted, you will have to empty and fill it.

A few things I can add.

Using nitrogen is best but it won't make too much of a difference as I doubt you'll be getting the forks very hot. But...we use nitrogen...mainly because it's there not because we really think it's going to make a difference. The WP manual does not specify N2.

The silicon plug that allows you to fill the bladder with a needle will sometimes leak, and you will either have to replace the plug...or quickly put the screw back in place. The plugs are available from KTM.

Lastly, there is a pressure relief valve on the side of the cartridge that likes to leak. The main cause is because of dirt in the fluild and the best way to fix it is to replace the spring and the o-ring. For now, about the best you can do is to just clean it, but don't use a solvent as the o-ring will freak out.

These forks are a little tricky so you're not alone.

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Thanks guys I really appreciate your tips.

will this needle work

http://pitposse.com/ninekit.html

I have a N2 low pressure setup at work I think I can use.

Yes that will work. Like others said N2 is ok but so is air. I like my little hand pump as its easier to use at the track so I can make pressure changes while testing.

doc

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I would agree with Doc and Dave. We use N2 "because it's there" and we just like to be consistent. In the fork, air should be fine.

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So if your just doing seals, is that outer oil only? And what is the air gap for a plush ride?

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what about changing the oil in the upper chamber would i have to release the pressure then in order to disassemble the upper cartridge?

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yes the inner cart is pressurised so you have to re pressurise it to work on it.

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