2020 KTM 450 SX-F Factory Edition Review First Ride

Just six days after testing the 2020 Husqvarna FC 450 Rockstar Edition at Glen Helen Raceway, we returned to the famed San Bernardino, California, track but this time for a private test day as KTM North America rented the National MX track for its 2020 KTM 450 SX-F Factory Edition introduction. With only a handful of media outlets in attendance, the track was not as rough as a usual Thursday practice day, but bumps still formed and the relatively smoother track conditions actually gave us a better impression about certain aspects of the bike.

The 2020 KTM 450 SX-F Factory Edition comes stock with an Akrapovič slip-on silencer. The other difference over the standard 2020 KTM 450 SX-F isn’t visible from the outside—it’s in the ECU mapping. In the past, maps 1 and 2 were always fairly similar—so much so that it was difficult to tell the differences between them. On the 2020 KTM 450 SX-F Factory Edition, map 1 is changed slightly, while map 2 is designed to be much more aggressive.

At the 2020 Husqvarna FC 450 Rockstar Edition intro at Glen Helen Raceway the week prior, we received, among other things, press information about the bike’s suspension, which we published in the first ride review. Being that the 2020 Husqvarna FC 450 Rockstar Edition and 2020 KTM 450 SX-F Factory Edition share the same suspension settings, rather than repeat the exact same information for the 450 SX-F Factory Edition, we felt it would be appropriate to get some additional insight about the two bikes’ new suspension setup from WP R&D suspension technician Leigh Crawford, who explained the changes more in detail.

The WP Xact shock features new SKF linkage seals with less drag, and a new shock setting has been implemented to accommodate the lower friction components. Also, a new O-ring is used that has a different durometer rating, which Crawford explained is more for durability rather than performance.

The most notable changes were made to the WP Xact air fork, one of which is that the bushing seat on the outer tube now has three notches cut in it to accommodate bleed-off between the bushings. Crawford said that as the fork extends and the bushings get close together, there is essentially a chamber in there. The three notches eliminate the potential for pressure to build up in the chamber and are therefore intended to make the fork action smoother and more consistent through the stroke.

Another part that has been significantly updated is on the air cartridge. WP air forks have one Schrader valve, which charges the negative chamber and the positive chamber at the same time with what it calls a bypass.

“The bypass is essentially a notch that is pressed into the side of the cartridge that is aligned with the seal head,” Crawford explained. “When the bike is on a stand, the seal head positions allow for the air that you’re inserting in through the Schrader [valve] to reach both sides. We’ve now extended that bypass—it’s almost twice as long as it was before—and what that does is when the front wheel touches the ground, it has a little more set-in before it closes the bypass. At the point where it closes the bypass, you start to build pressure in the positive chamber and you start to build vacuum in the negative chamber, so it just eases that a little bit.

“Along with that, we also changed the air volume spacer,” Crawford continued. “The 2019 and 2020 air volume spacer is quite large and basically made the air volume in the negative chamber quite small. We’ve now gone to one that is smaller than that, and that’s again balancing out the bypass.”

An additional update is on the piston. The prior component had a single small hole, whereas the new piston has four larger ones.

“We use the inside of the cartridge rod as part of the volume,” Crawford noted. “The fluid dynamics of air could affect how the vacuum is going inside or out of the rod, so [the increase of holes and the size of them] makes that less of an issue.”

WP has also made several updates to the compression side including a rebound adjuster that can be adjusted by hand, eliminating the need for a screwdriver to make rebound clicker changes. That’s the external difference, but there are a lot more changes internally made to the mid-valve in an effort to give the fork sufficient holdup, but not be too stiff as the speeds increase, and provide the rider with plenty of tuning capability.

“On the mid-valve, we went to a design that has the potential to be built as a floating or a lift height setting, but in the case of the motocross bikes, we’re building this as what they call a trampoline setting,” Crawford concluded.

Both maps on the Factory Edition are improved over the standard model—most notably map 2 (aggressive). Map 1 (stock) on the Factory Edition is a bit livelier than it is on the standard model, while map 2 has a significantly increased torque feel from the low-end to midrange—so much so that I felt comfortable riding a gear high through corners, whereas with map 1 in the same turn, I would have had to use the clutch more or even opted to downshift.

Being that there wasn’t the usual massive acceleration and braking bumps on the Glen Helen main track, map 2 was my preferred setting. Interestingly, when testing the 2020 Husqvarna FC 450 Rockstar Edition the week prior on the same track but during a public day, I opted for map 1 due to its controllability on the bump-strewn course. I am pleased that KTM has made a concerted effort to make the two available maps different, especially by making map 2 live more up to its name.

Another preference of mine, which applies to the 450 SX-F Factory Edition and the standard model 450 SX-F, is the optional, faster-turn black throttle cam. The reason for this is because with the stock, slower-turn gray throttle cam installed, I notice that I have to turn the throttle very far before hitting the stop, whereas the black throttle cam decreases that chicken wing feeling.

The significant amount of updates made to the WP suspension were also noticeable on the track. Compared to the standard 450 SX-F model, the Factory Edition’s WP Xact air fork has a suppler feel in the initial part of the stroke, thereby decreasing feedback into my hands and arms on braking bumps. Although, in comparison to the 2020 Husqvarna FC 450 Rockstar Edition, the 2020 KTM 450 SX-F Factory Edition seems to offer just slightly less comfort on small bumps. Being that the two bikes share identical suspension settings, I would isolate that to the more rigid Neken bar on the KTM in comparison to the ProTaper bar on the Husqvarna. If I owned a Factory Edition, the stock handlebar would be an item I would swap out in favor of a bar with a similar bend, but one that offers more flex.

To a minor extent, the Factory Edition’s revised shock seemed to absorb acceleration chop and braking bumps better than the standard 450 SX-F model. Another important thing to note is that both WP units are very sensitive to changes. Two clicks softer on the fork compression made the front feel plusher, but it also caused it to ride lower in the stroke, thereby giving the bike somewhat of a high rear end stance sensation. I split the difference by going one click firmer on the compression from that point, resulting in one click softer than the stock fork setting, which provided better comfort while still maintaining a proper balance from front to rear.

One of my favorite KTM PowerParts items on the Factory Edition is the factory seat. The ribs and material of it offer tons of grip and makes it easy to stay in place when sitting, especially when accelerating hard out of corners and blasting up the hills of Glen Helen.

With its more aggressive engine character and plusher suspension settings, the 2020 KTM 450 SX-F Factory Edition is certainly an improvement over the standard 2020 450 SX-F model. If the new ECU mapping and suspension changes find their way onto next year’s 450 SX-F, and we’re willing to bet they will, 2021 will be another very good year for KTM’s flagship motocross bike.