There has been so much confusion and misinformation regarding the 2013 Kawasaki KX450F Kayaba PSF (Pneumatic Spring Fork), that we decided to corner one of the guys helped develop the fork in question. Dan Worley worked as a development technician for KYB for 11 years before moving on to start his own business earlier this year, SDi. He saw the PSF through it's early stages all the way to mass production and already has a few years of experience with what has become known as the "air fork." If anyone knows the proper way to adjust and monitor the PSF on the KX (and 2013 Honda CRF450F) it's Dan.

Proper Setup for the 2013 KX450F KYB PSF Fork - More Motocross Videos

Proper Setup for the PSF Made Easy

1. Know Your Gauge

a. Know how much pressure is lost from attaching your gauge and adapter setup.

b. To check this, attach your gauge and see what pressure is in the fork.

c. Loosen the gauge completely, and attach it again.

d. Notice how much the pressure changes from the first time you checked - that is how much pressure drop is from the gauge itself.

e. Know what pressure you like on your gauge. There are so many cheap gauges out there that have huge tolerances. If you like 33 psi on your gauge, remember that, and don’t worry if your buddy’s gauge says something different.

2. Check Your Pressure Every Morning

a. Check your pressure every morning before you ride! Your suspension will not work correctly if you don't!

3. Mid-ride Adjustments

a. When checking/adjusting pressure during the day, you must add or subtract from the pressure that the gauge reads then, NOT from your morning base setting.

b. As the fork gets warm, the pressure will increase.

Example: If you start at 35psi, and you want to go stiffer after the bike is warm then you should check the current pressure. If it is at 37psi, you must add 1psi PLUS the amount you lose from attaching your gauge (typically about 1psi; see section 1).

c. If you want to go softer, and your gauge loses 1 psi every time it is attached, you will only need to attach your gauge to go 1 psi softer (since you automatically lose 1psi when you attach your gauge).

d. Finally - Do no Panic if you started at 35 psi and it increases to 40 psi! This is most likely from the cartridge heating the air after riding and not having oil splashing around to cool it.

4. Adjusting The Air Pressure is a Huge Asset

a. It does more than act as a stiffer spring - remember it adds friction, which acts like low speed damping!

b. It is important to find your upper limit on air pressure and initial fork comfort, to much air can make initial movement harsh.

You must play with the balance between the compression clicker adjustment and air pressure.

-Dan Worley

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