INNTECK WP Open Cartridge Fork Springs for KTM EXC, EXCF, SX, SXF and HUSABERG FE 390, 450, 570 2002-2016

The INNTECK WP cartouche ouverte pair of fork springs is designed for KTM EXC 125, EXC 200, EXC 250, EXC 300, EXC 500, EXC 520, EXC 530, EXCF 250, EXCF 350, EXCF 450, SX 125, SX 250, SXF 250, SXF 450 and HUSABERG FE 390, FE 450, FE 570 from 2002 to 2016. The spring rate sets the height at which the fork works in its travel. With springs matched to your weight, the front end holds its attitude under braking and on landings, and the damping adjustments get back into their effective range.

Specifications

• Brand: INNTECK
• Manufacturer part numbers: QS2438, QS2440, QS2442, QS2444, QS2446, QS2448, QS2450, QS2452
• Diameter: 43.2 mm, length: 505 mm
• Sold as a pair (one spring per fork leg)
• Available versions: 3.8 N/mm: ref. QS2438; 4 N/mm: ref. QS2440; 4.2 N/mm: ref. QS2442; 4.4 N/mm: ref. QS2444; 4.6 N/mm: ref. QS2446; 4.8 N/mm: ref. QS2448; 5 N/mm: ref. QS2450; 5.2 N/mm: ref. QS2452

Choosing the right spring rate

Start from the original spring rate (see the bike's manual) and adjust for your riding weight with gear: heavier than the standard rider, go up one step; lighter, go down one step. In enduro, people often choose something a little softer than in motocross for extra comfort.

When to replace it?

• The fork bottoms out often or dives hard under braking: springs too soft for you.
• The front end sits high, bounces and the bike understeers: springs too stiff.
• You weigh clearly more or less than the standard rider the manufacturer designed for.
• Springs sagged after many hours: the fork sits lower in its travel than it did originally.

Spring rate is given in N/mm. Manufacturers also quote it in kg/mm: 1 kg/mm is about 9.81 N/mm (0.46 kg/mm ≈ 4.5 N/mm). Check the type and diameter of your fork: the spring must have the right length and diameter.

Fitting tips

1. Note your settings and the height of the tubes in the clamps, then remove the fork.
2. Open each leg following the manual for your fork and replace the spring, reusing the original washers and spacers.
3. Reset the fork oil level to the height given in the manual: it affects the end of the stroke.
4. Refit the fork and tighten the clamps to the specified torque, then check the front rider sag.

Spare parts and items to plan

• Fork oil : LIQUI MOLY 10W 500 ml
• Fork oil seals : ATHENA P40FORK455141 · ATHENA P40FORK455069

Frequently asked questions

Do I have to change both springs?
Yes, always as a pair, with the same spring rate on both sides, except on forks with a single spring.

Are springs enough to transform the fork?
They put the fork back at the right height for your weight. The damping is then adjusted with the compression and rebound clickers.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
HUSABERG FE 390 2010
HUSABERG FE 390 2009
HUSABERG FE 450 2010
HUSABERG FE 450 2009
HUSABERG FE 570 2010
HUSABERG FE 570 2009
KTM EXC 125 2016
KTM EXC 125 2015
KTM EXC 125 2014
KTM EXC 125 2013
KTM EXC 125 2012
KTM EXC 125 2011
KTM EXC 125 2010
KTM EXC 125 2009
KTM EXC 125 2008
KTM EXC 125 2007
KTM EXC 125 2006
KTM EXC 125 2005
KTM EXC 125 2004
KTM EXC 125 2003
KTM EXC 200 2015
KTM EXC 200 2014
KTM EXC 200 2013
KTM EXC 200 2012
KTM EXC 200 2011
KTM EXC 200 2010
KTM EXC 200 2009
KTM EXC 200 2008
KTM EXC 200 2007
KTM EXC 200 2006
KTM EXC 200 2005
KTM EXC 200 2004
KTM EXC 200 2003
KTM EXC 250 2016
KTM EXC 250 2015
KTM EXC 250 2014
KTM EXC 250 2013
KTM EXC 250 2012
KTM EXC 250 2011
KTM EXC 250 2010
KTM EXC 250 2009
KTM EXC 250 2008
KTM EXC 250 2007
KTM EXC 250 2006
KTM EXC 250 2005
KTM EXC 250 2004
KTM EXC 250 2003
KTM EXC 300 2016
KTM EXC 300 2015
KTM EXC 300 2014
KTM EXC 300 2013
KTM EXC 300 2012
KTM EXC 300 2011
KTM EXC 300 2010
KTM EXC 300 2009
KTM EXC 300 2008
KTM EXC 300 2007
KTM EXC 300 2006
KTM EXC 300 2005
KTM EXC 300 2004
KTM EXC 300 2003
KTM EXC 500 2016
KTM EXC 500 2015
KTM EXC 500 2014
KTM EXC 500 2013
KTM EXC 500 2012
KTM EXC 520 2006
KTM EXC 520 2005
KTM EXC 520 2004
KTM EXC 520 2003
KTM EXC 520 2002
KTM EXC 530 2010
KTM EXC 530 2009
KTM EXC 530 2008
KTM EXC 530 2007
KTM EXCF 250 2016
KTM EXCF 250 2015
KTM EXCF 250 2014
KTM EXCF 250 2013
KTM EXCF 250 2012
KTM EXCF 250 2011
KTM EXCF 250 2010
KTM EXCF 250 2009
KTM EXCF 250 2008
KTM EXCF 250 2007
KTM EXCF 250 2006
KTM EXCF 350 2016
KTM EXCF 350 2015
KTM EXCF 350 2014
KTM EXCF 350 2013
KTM EXCF 350 2012
KTM EXCF 350 2011
KTM EXCF 450 2016
KTM EXCF 450 2015
KTM EXCF 450 2014
KTM EXCF 450 2013
KTM EXCF 450 2012
KTM EXCF 450 2011
KTM SX 125 2006
KTM SX 125 2005
KTM SX 125 2004
KTM SX 125 2003
KTM SX 125 2002
KTM SX 250 2006
KTM SX 250 2005
KTM SX 250 2004
KTM SX 250 2003
KTM SX 250 2002
KTM SXF 250 2006
KTM SXF 450 2006
KTM SXF 450 2005
KTM SXF 450 2004
KTM SXF 450 2003
KTM SXF 450 2002