Kawasaki have always been very progressive when it comes to developing their motocross line. Liquid cooling, disk brakes, perimeter frames and even the fluorescent colors are all innovations from the Japanese brand.

This year will be recorded as the year Kawasaki introduced the Showa SFF-Air TAC (Triple Air Chamber) fork to the public. Of course there are many things updated and refined on the new KX450F but the big news is the addition of the Showa TAC fork. This is the same fork that many of the factory teams have been using for the past two racing seasons and it is the direction of the future.

The three separate chambers give you an infinite range of adjustability for rider weight, speed and rider preference. The inner chamber has a direct effect on ride height, so if you want the fork to ride higher in the stroke you add air pressure there or reduce pressure for a lower ride height.

Image: Matty Fran.

The outer chamber changes the bottom of the stroke so if you want a firmer/softer feel deeper in the stroke you add/remove air there. The bottom chamber is a negative chamber that actually offsets the pressure from the top two chambers. This has the biggest effect on the initial feel of the fork.

Small chop and chatter would be addressed by working the air pressure in this chamber. With this much adjustability there is certainly a learning curve for every rider and I believe that is why we are hearing mixed reviews from pro riders about the fork.

The left leg of each fork controls the damping with a compression adjuster on top and a rebound adjuster at the bottom. The right fork hosts the three chambers and has two Schroeder valves on the top and one on the bottom for the negative chamber.

Image: Matty Fran.

Aesthetically, the outer tubes on the new Showa fork have a machined silver finish that looks exactly like what Ryan Villopoto and the factory Kawasaki team used all year.

The 2015 Kawasaki also pairs the new fork with a new Showa shock to balance out the machine. The shock is anodized a dark color and surrounded by a bright green coil spring giving it a very unique look. Additionally, every KXF450 comes with a shock pump that is perfect for adjusting fork air pressure.

Other changes on the big, green machine include ECU updates, a self-locking axle (which means you’ll no longer need to buy an industrial-sized box of cotter pins), a bridged box piston that increases compression and air flow inside the engine, a lighter sub-frame, green anodizing on the engine parts and a green shock spring, larger 270mm front rotor (a Braking model) with a 240mm rotor on the rear and lighter axles.

Image: Matty Fran.

The KX-F also features adjustable footpegs [5mm up or down], adjustable clamp and ‘bar mount for four positions, plug-in couplers and an optional DCI kit that allows you to choose your own mapping. Kawasaki has really made an effort to make this bike adjustable so that riders of any size or skill level can fee like it has a personalized fit and feel.

My day of riding the new model began by getting an overview of all the changes from the Kawasaki technicians and chatting with the Showa engineers about how the TAC fork works. I was shown graphs and charts that explained what air pressure changes in each of the chambers would do in terms of feel on the track.

I started to feel like I was in an introduction to Trigonometry lecture. The excess of information really did help me understand how to make changes based on what I felt the fork doing. I was just getting anxious to actually throw a leg over this thing!

Image: Matty Fran.

My first impression of the 2015 KX450F was the same impression I had when I rode last year’s model: Damn, this thing is quick! The engine is simply amazing on the Kawasaki. There is an abundance of torque that rolls right into all the over rev you could want. And the way the power is delivered makes it very rider friendly and usable.

After enjoying the horsepower for a few laps I came in for my first adjustment. The sag was spot-on, but I felt the front end dropping too low into the stroke when I would grab the front brake hard or G-out into a jump face. I found the Showa guy and asked what he thought I should do. Of course he referred me to the chart and explained that adding air to the inner chamber would lift the ride height of the fork. We added eight psi to the inner chamber with the shock pump supplied by Kawasaki and off I went.

The change took somewhere around 90 seconds and was equivalent to changing to a stiffer fork spring. On the track the change was immediately noticeable. The fork was up where I wanted it and the balance of the bike was perfect. The track was not very rough, but I wanted to make a few changes with the fork so I could understand what they would feel like on the track.

Image: Matty Fran.

I figured I could get the front to gobble up some of the small chop a little better if I reduced pressure in the outer chamber so we dropped it 2psi. The feel was definitely more supple and soft but it also changed the way it tracked the ground entering corners and working through sweepers. It was better in some areas and I didn’t like it as well in others. This is where it can get tricky in terms of testing to find the right setup.

I could try turning in the compression clickers on the left fork or we could add some air back into the outer chamber and split the difference; the possibilities are endless in terms of options. That is great news for someone who likes to tinker with their bike, but it could be frustrating for a guy who just like to put gas in it and go ride.

The Showa tech did say that they use nitrogen with all the race teams because it tends to maintain pressure more evenly than room air (same reason they use it in tires). He also said to make sure not to use an air compressor when adding pressure to the forks because the moisture that builds up inside the compressor tanks is very damaging to the fork.

Image: Matty Fran.

I walked away from this bike introduction very impressed with the new Kawasaki and not nearly as intimidated by the new fork technology. The KX450F has a class-leading motor, a very strong new front brake, a comfortable and very adjustable chassis and rider cockpit and the very latest in suspension technology.

Anyone thinking about going down to a Kawasaki dealer and buying green this year will not be disappointed. Now available in local dealerships, the revamped KX450F has an RRP of $10,999 in Australia.

Note: All images posted are of David Pingree’s fellow Racer X test rider, Sean Borkenhagen.