KTM introduced a heavily revised 450 SX-F model last year. Some of the major updates were a more compact cylinder head, a frame that had a 2-percent increase in longitudinal stiffness and a 10-percent increase in torsional stiffness, and new suspension settings to match with the more rigid chassis. Compared to its predecessor, the engine was less responsive off the bottom, and the suspension and chassis changes made for a less comfortable ride. KTM listened to the feedback from the media and its customers, and went to work to refine it for MY20. We rode the 2020 KTM 450 SX-F at Fox Raceway in Pala, California, for the first time to see how the changes the Austrian manufacturer made to its flagship motocross bike felt on the track.
The 2020 model comes with a new CP piston that is designed for better durability and to offer a more free-revving power. The EFI mapping is unchanged in map 1, but has changed in map 2. Map 2 seems to be more aggressive and more powerful overall. In an effort to gain a little more power and better throttle response, the Austrian manufacturer includes a new, aggressively vented airbox cover with the bike, which can be installed without tools. The final change KTM made to get more in regards to getting a snappier type of power from the bike was the final drive ratio, as they went from a 48- to a 49-tooth rear sprocket.
With the new optional vented airbox cover and a larger rear sprocket, you immediately notice an improvement in throttle response and power delivery. We liked the light engine feel and good throttle response, as this helped make the bike a little easier to move around the track and hop over bumps. Maps 1 and 2 are noticeably different and both have good characteristics, which makes choosing which one to use more of a track-specific decision. Map 1 might be better in more slippery or hard-packed conditions. Map 2, which offers more torque and overall power, might be better optimal traction conditions such as loamy soil. Additionally, with traction control (TC), you can fine-tune both maps to give you even more options.
With the new 13/49 gearing and more powerful engine, we found ourselves using third gear in all areas but the tightest corners. Third also revved quite far; it was low enough that it was usable in corners, but it revved out far enough that shifting wasn’t required on medium-length straightaways. Shifting to fourth was also an option that could be used to calm the engine down for those who don’t like riding in the high rpm, and of course to go even faster. The Brembo clutch action is very consistent and easy to modulate, which helps make the gearbox shift very well.
In addition to the optional vented airbox cover, KTM includes a black (shorter turn) throttle cam. The black cam is an immediate change, as the throttle pull with the stock gray throttle cam is just too long in comparison to the Japanese bikes.
The WP Xact fork and WP Xact shock that come on the 2020 KTM 450 SX-F are similar in design to the units that came on the 2019 450 SX-F Factory Edition model. However, they are updated with different valving that is designed to improve comfort and a new mid-speed piston in the fork, which is manufactured with even tighter tolerances. The fork offers a noticeably improved ride. It’s a more comfortable setting with the biggest improvement being in the initial feel or movement. The shock changes complement the fork and seem to increase rider comfort. The most noticeable change was how the bike would squat on acceleration after the apex of the corner. This squatting helped increase rear wheel traction and, because it was only noticeable after the apex, it did not affect corner entry.
We made changes to the fork and shock on our first day of testing. The air fork tends to ride a little high in the stroke, so we raised the fork in the clamps to lower the front end and increase pressure on it. The bike was a little busy, so we slowed the rebound down four clicks front and rear. We liked the squatting sensation on acceleration, but found it to be just a touch too noticeable. To combat that, we went a quarter-turn in on the high-speed compression on the shock. This was just enough to help with a little hold-up but not reduce traction.
Lastly, the stock Neken handlebar is a bit rigid, and we’d prefer one that offers more flex. Some test riders would prefer a shorter-length bar as well.
Last year, we criticized the 450 SX-F for several things that we didn’t like and KTM listened. On the 2020 model, engine power and throttle response is up, the base suspension settings are much more in a usable or adjustable range, and rider comfort is significantly improved. KTM really did a good job with their updates. When riding the bike, test riders felt much more comfortable on it. The engine power is light, free, and fun to ride. The suspension felt softer, but still very much like a race setting with good hold-up and bottoming resistance.
Helmet: Shoei VFX-EVO
Goggle: Scott Prospect
Jersey: Thor Prime Pro Jet
Gloves: Thor Rebound
Pant: Thor Prime Pro Jet
Boots: Alpinestars Tech 10
