Stage 1 Off-Road Race Build
Story by Trevor Hunter, Photos by Trevor Hunter/Mark Kariya
Since the 2025 KX450X is largely unchanged from 2024 (new graphics, a new air filter, and updated ECU perameters make up the changes), we had a good head start when building out our new KX450X to go racing in the AMA National Grand Prix Championship. We still have a few different parts to try on this bike before we call it a final build; however, we’re very happy with the current setup and thought we’d share where we’re at with it and how it performs on the track. To check out our 2024 build, click HERE.
TCS Powersports transferred our 2024 setup to the 2025 model. We’re currently using a variation of the stock valving, sticking with the same style but with more dampening to accomodate for the faster speeds with a Pro level rider onboard. The stock settings are a good start and for the average rider they are very rideable, but for fast riders in fast terrain it just wasn’t quite enough.
Different from the ’24 bike, we now have a Pro Circuit Ti-6 full system on the bike. The power delivery is quite different between the two exhausts, and we’ll have a more in-depth comparison on them, but in short, the PC exhaust has a more aggressive power delivery.
In the cockpit, we’re running Pro Taper Contour CR Mid handlebars for a bend that we like and more comfort out of the handlebars. The Pro Taper offerings take a touch of harshness out of the front end from the stock Renthal handlebars. The Precision Racing Steering Dampener minimizes headshake and mounts directly to the handlebars, eliminating the need for any special triple clamps or bar mounts.
The Works Chassis Lab motor mounts helped us find a “better” chassis feel on this bike with some more comfort and precison. You can read the full Product Test HERE to see what we thought of all of the options and which one may be better for you, but I preferred the Stiff tops and bottoms on this bike with the current suspension setup.
DT-1 Filters has a screenless, domed air filter setup for the bike that enhances power slightly, but also adds volume to the filter so it doesn’t get clogged up as fast. You can read the full Product Test HERE.
IMS’ 2.8 gallon tank ensures we can go the distance and have quick pit stops with the dry-break assembly.
I’m a big fan of the extra grip that the Guts Racing Wing Seat provides, and it works well on the KX. You can read the full Product Test HERE.
Because it’s a sand track, we ran a Maxxis MX-SM scoop tire to power through the deep sand of Blythe and Lake Havasu. Maxxis only makes the tire in a 19 in offering, but we like the more solid 19 in wheel in the deep sand whoops that these tracks offer.
The front tire is a 80/100-21 MX-SI from Maxxis and both wheels are stuffed with Airmousses. The Airmousse is light and maintains good handling characteristics as a result while still maintaining good durability if running the correct size.
P3 Carbon’s Skid Plate protects the vitals on the undercarriage in a slim fit skid plate while providing adequate protection.
The Corner Coach is one of our favorite tools to use on our race bikes as we can adjust where we put the bump for different tracks and terrains. In the sand, we move the bump back on the seat slightly to sit further back in the deep sand while still having the benefits on running a bump.
