WHAT IS IT? A cost-effective fix for the front and rear WP suspension components on KTMs.

WHAT‘S IT COST? Forks, $295.00 (plus oil); shock, $195.00 (plus oil and spring).

CONTACT? http://www.mx1suspension.com or (916) 741-8767.

WHATS IT DO? When it comes to KTM mods, Richard Wilk is a legend. He has been working on motorcycle suspension since 1980, and he doesn’t specialize in factory racers, $7500 works components or finicky National riders. Instead, Wilk’s MX1 Suspension company focuses on real-world racers with real-world problems at real-world prices.

WHAT STANDS OUT? Here’s a list of things that stand out with the MX1 Suspension KTM setup.

1. Forks. On the WP forks, MX1 tried many different combinations of oil heights, valving and compression pistons to find the perfect flow rates. What worked best on the 2009 KTM 450SXF was the stock 0.50 springs, 375cc of oil, plusher mid-valving, stiffer rebound and MX1's proprietary HFP (hi-How pistons). The stock threeport compression pistons were replaced with higherflowing two-port pistons. This design also lets the shims flex in a more natural way. Stock springs were utilized. Bladder pressure was also altered for more initial plushness.
2. Shock. MX1’s goal was to give racers a relatively inexpensive fix for the stock KTM shock. MX1 didnt want to design a bevy of expensive special parts. They focused on the valving to improve plushness on square-edge bumps. The rebound was increased to match MX1’s stiffer progressive—rate spring (7.6 to 9.5kg/mm). For racers experiencing shock fade, MX1 offers a $179 anti-fade shock reservoir to solve the problem.
3. Fork performance. We loved the forks. Most MXA test riders think that KTM improved the stock KTM 450SXF forks for 2009, but didn't make big enough strides in plushness. The stock forks feel harsher and stickier than necessary from the midstroke on. MX1 opens up the flow enough to make the WP forks feel plush without allowing them to bottom (which is what happens when you lower the oil height). MX1's forks were spot-on.
4. Shock performance. First and foremost, MXA believes that no-link suspension can work, but the focus needs to be on the rising rate, not the shock. Unfortunately, KTM has built a shock-sensitive rear suspension system—and they have not provided enough shock to do the job. Our quick fix has always been to go much stiffer on the spring and use the clickers to control it. MX1’s solution is much better. They go even further on the spring rate (further than the 7.6 kg/mm spring that MXA uses), but they opt for a progressive-rate spring that starts softer and ramps up much more. Then MX1 increased the rebound damping to control the recoil.

Every test rider liked this feel, because it didn't force them to choose between running the shock stiff to avoid bottoming or soft to get a good feel through the bumps. The MX1 shock handled both well.

What's the Squawk? No complaints.

MXA Rating 5 stars

We loved the MX1 forks mods and liked the shock (Although not as much as the forks). MX1 figured out how to make WP suspension components plush without bottoming. That is like an ice cream sundae that doesn't make you fat. Good stuff.

Motocross Action, September 2009 page 149