KTM Fork Fix

By Dr . Dirt

 

Have you checked the air pressure in your KTM forks lately? Most people don’ t are aware of it but the WP Twin Chamber forks on most 2007-2014 KTM SX/SX-F versions, 2008- 2013 XC/XC-F models, several 2014 Husqvarna, and some Husaberg versions have an air bladder that needs to be checked periodically. WP uses an air bladder instead of a pressure spring (like those on Showa or KYB forks) to help control damping. The bladder is used to pressurize the particular oil in the inner chamber therefore air cannot mix with the essential oil. If your forks are underperforming or you just haven’t had them serviced in a long time, this is for you.

 

KTM Fork Fix // Photo: Adam Booth

There are two Philips head screws on top of the twin holding chamber fork. One screw is easy to reach and is used to bleed trapped air from inside the fork. The other screw is certainly partially blocked by the compression adjuster and gives access to the air bladder. Don’ t worry, the bladder is a sealed unit and will not leak when you unscrew it.

 

KTM Fork Fix // Photo: Adam Booth

A 0-30 psi suspension pump and suspension needle work better to check the pressure. Turn the compression setting adjuster to a place where you can remove the screw and puncture the bladder with the needle. It should read seventeen psi. If it is low, pump it up.

 

If the pressure is high you have another problem and this often comes from riders who bottom the fork often. Oil from the outer holding chamber has bypassed the one-way essential oil bleed valve on the inner holding chamber and compressed the bladder against the cartridge. The increased pressure makes the damping harsher and the loss of essential oil from the outer chamber makes the fork easier to bottom out.

 

KTM-ForkFix-03 KTM-forkfix-04 KTM-ForkFix-05

To remove the excess oil, unscrew the inner chamber from the external with a 50 mm fork cover wrench. You can leave the forks on the bike but you have to remove the handlebars to gain access or you can remove the forks from the bike. Once the inner chamber is exposed, insert the particular needle and gauge into the bladder, bleed the excess oil out the bypass valve, and when the pressure evaluate reads 17 psi, STOP! Allow the excess oil run into the external chamber.

 

Do this periodically and your forks will work great!


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