Ryan Nitzen | June 9, 2022

So many bikes, so little time. We sample the latest SX-F four-stroke motocrossers from KTM.

Sometimes it’s hard to ride just one.

Photography by Jesse Ziegler and Mack Faint

The perfectly manicured grass of Michigan’s RedBud Motocross facility is a far cry from the desert hillsides of Southern California where I grew up. You can literally feel the venue’s history, the buzz and the mystique as you enter through the gates. And while the stands and parking lots were empty for our mid-week arrival, the vibe was unmistakable. This was the site of KTM’s 2023 model introduction, a private day ride-fest at one of the most iconic tracks in American motocross.

A three-and-a-half-hour drive from KTM’s Ohio warehouse, RedBud served as our honorary test site for the new SX, SX-F, and XC-F lineup. The Orange Brigade loaded up the haulers with over 60 bikes and practically made RedBud look like the newest KTM dealership way out in the Michigan countryside. For this review, however, we’ll be focusing only on the SX-F models, there are just too many bikes to talk about in just one sitting. When it comes to the SX-Fs, three new four-strokes serve as the flagship motocross bikes from the Austrian brand.

Technically, we previewed the 250 and 450 back in February when we rode the 2022 KTM Factory Editions. The Factory Editions typically serve as a preview for the coming model year and low and behold, history repeated itself. These new 2023 SX-F’s debut the same structural changes we saw on the Factory Editions—most notably, a new frame and a new engine, wrapped entirely in new bodywork. For ’23, think Factory Edition without the extra anodized bolt-ons.

In typical KTM fashion, all three of these bikes, the 350 now included, share many of the same parts. Basically, anything but the actual engine is nearly interchangeable among the four-stroke motocrossers. In fact, the moto-specific bikes set the tone for the rest of the KTM lineup, as the XC-F models sport the same frame, electronics and bodywork designs. The new frame eliminates the previous “backbone” that ran from the shock tower up to the steering stem. Without that upper spar, energy loads are said to transfer down the sides of the frame instead of up through the handlebars.

2023 KTM Four-Stroke action
These all-new KTMs will inspire you.

The powerplant is another big talking point as it’s also been re-worked for this new generation. The engines have been rotated back in the frame two degrees with the countershaft sprocket being lowered by a few millimeters. This allows the engine to be nearly two inches shorter than the previous generation in hopes of improving centralized mass and eliminating suspension squatting when riders are hard on the gas. A comprehensive electronics package is fitted standard with two maps, traction control and quickshift options (all five-speed four-stroke models have quickshift that works from second to fifth gears). We like the clean and simple design of the buttons as they’re easy to use and understand.

All three bikes continue to ride on WP Xact Aer forks and Xact rear shocks. This is the same componentry we’ve seen for a few years now, but the WP techs informed us that they’ve had more time to perfect settings for the latest bikes. A new hydrostop in the front fork aids in bottoming resistance, which we were pleased with after riding the Factory Editions. Right away the fork felt much more predictable and less vague, my favorite version of the air fork to date. Both the fork and shock now offer tool-less adjustability, with simple hand dials being fitted on the outside of the respective part. This allows riders to make clicker adjustments on the fly with the turn of the dial.

The overall cockpit is thin and racey, just as you’d expect from KTM. The radiator shrouds on all the SX-F’s maintain that KTM slimness but have been redesigned with a longer front-to-back shape. So long that they almost touch the front fender when the bars are locked on either side. But no worries on that as they don’t interfere with anything and aren’t too noticeable while riding. A new seat design and wider footpegs complete the rider triangle.

2023 KTM 450 SX-F
As expected, the 2023 KTM 450 SX-F is the “standard” version of the latest Factory Edition, same with the 250.

2023 KTM 450 SX-F

Let’s talk about power. If you’re familiar with the 450 SX-F, you’ll recognize it for that long usable powerband. It’s become known as one of the longest revving bikes in the class with a huge mid-to-top range. For ’23, they’ve kept that same character but added heaps in the bottom-to-mid range. It still revs up near that five-digit rpm range but with a more responsive hit down low, the bike requires less nurturing to get it up into the meat of the power.

The electronics are also much more distinct. Map two is obviously different from map one, where in years past the changes were far more subtle. The second map is much more aggressive from bottom to top with a harder hitting, more Japanese style power curve. This will certainly be the choice for faster or more experienced riders, while map one feels more familiar to KTM’s in years past. Quickshift and traction control also come standard on the 450 SX-F. The loamy conditions at Red Bud did not beg for traction control, but the quickshift was a fun option to play with on the fast-flowing straightaways.

2023 KTM 350 SX-F
The KTM 350 SX-F also gets the Factory Edition treatment.

2023 KTM 350 SX-F

Ah yes, the 350. The often-overlooked welterweight of the big-bike motocross world. The middle child of the KTM family if you will. I haven’t spent much time on the 350s over the years and this was the only bike of the SX-F bunch that I had yet to ride before the RedBud intro (KTM did a combined 250 and 450 Factory Edition launch earlier in the year at Fox Raceway). By the end of the day, the 350 jumped up in the rankings as my favorite four-stroke.

What I like so much about the 350 is its overall versatility. Riding a 450 is fun, yes, but it takes a lot of effort to muscle that thing around at a race pace for more than just a few laps. Most of the time myself, or most of the motocross community, isn’t riding a 450 to its full potential. Plain and simple. Riding a 250 is also fun, but at six-foot-one and 180 pounds, I’m definitely on the bigger end for the small-bore machine. And similarly, the 450 is sometimes too fast in a sense, I feel there are the same number of times where I’m pushing the 250 into dangerous rev limiter territory. That’s where the 350 fits in. You can ride it hard like a 250, but also lug it like a 450 if needed. It’s a surprisingly nice in-between area of power that I didn’t know I needed. The 350 likes to be revved out and worked best when held wide open around the fluffy outside lines. Map two gave KTM’s middle child a little extra oomph that was welcomed in the deep conditions. The second map made the 350 more 450-ish and unlocked more ability to clear jumps from the inside lines. The 350 SX-F also receives the same changes as its bigger and smaller siblings in the way of a new frame, swingarm, plastics and electronics.

A small number of riders have tried their hands at the 350 in full race competition, Tony Cairoli and Mike Alessi quickly come to mind, but I still think it’s overlooked. I personally felt fastest and most comfortable all around on this bike and am anxious to ride it again on more familiar terrain.

2023 KTM 250 SX-F
You’ll notice a big difference between the ’22 and ’23 250 SX-F. We did.

2023 KTM 250 SX-F

The smallest of the SX-F models continues the theme with a full redesign in 2023. Like we said, the ’22 Factory Edition was a likely preview of what’s to come and the Orange Brigade certainly delivered. As with the 450, the mass centralization of the 250 engine, along with an 8mm reduction in engine height, helps fight unwanted “squatting characteristics” when under a load. The 250 receives a larger bore (81mm versus 78mm) and a shorter stroke (48.5mm versus 52.3mm) for the 2023 model year. While the engine still revs out to a mind-boggling 14,000 rpm, these changes produced a much punchier feel in areas that needed it most. Both the Yamaha and the KTM 250s often finish neck and neck in our shootouts, funny enough since they have previously been two of the most contrasting engines in the class. With the revised engine package, the KTM feels much more on par with the throaty lower-end of the Yamaha and the new Honda. Again, picture Japanese hit in an Austrian chassis.

The 250 SX-F hauled us around the deep conditions of RedBud without a complaint. Map two’s more aggressive nature quickly prevailed as the favored setting. It pulls strongly down low, flows nicely into that long KTM midrange, and still offers plenty of over-rev in the upper end of the curve. All of our riders felt comfortable right away on the new chassis, praising the new seat, footpegs and overall cockpit design. After a solid day of riding, we are eager to put this bike head to head against the other manufacturers.

2023 KTM Four-Stroke Motocrossers at RedBud
RedBud and seemingly an endless supply of the latest KTMs is not a bad way to spend the day. We’ll have quick reviews on the two-stroke SXs and XCs in a future issue.

Wrap Up

The 450 SX-F was picked as the favorite four-stroke from our designated pro rider, Matt Cerami. He preferred the big-bore KTM for its powerful, yet rideable engine character as well as the nimble chassis. While the new-gen KTMs did gain weight from the year prior, it really is hard to tell while riding (hint: if they don’t mention weight in the press releases, it means the bike got heavier, not lighter). The bike retains that scalpel-like feel that the orange bikes are known for and the WP Xact forks continue to improve across all models. Our riders agreed that the new 450 may have veered a bit from its traditional orange-bleeding vet market as the updated engine possesses much more bark down low. Some will prefer this and with proper tuning, the die-hard KTM owners can surely have their cake and eat it too.

Our intermediate-level rider, Ryan Nitzen, stayed right in the middle with his choice, picking the 350 SX-F as his bike of the day. The predictable power was more than the 250 but just slightly less than the bigger 450. This bred confidence on the track and an overall more enjoyable ride. There’s nothing better than flowing with the bike and not worrying that it’s going to whiskey throttle out from underneath you. For someone who’s on the fence about the in-between bike, try it and thank us later.

Our resident vet/off-road/smack-talker, Jesse Ziegler, favored the 250 SX-F out on the moto track. He claimed the 250 has more than enough power for his liking. With new mapping options and traction control, he could de-tune or up the power depending on track conditions or on how much his veteran arm pump was acting up that day. Younger riders and racers will obviously take to the 250 as they move through the ranks, but vets will also be surprised at its overall well-roundedness.

After riding almost 10 bikes in one day (it felt like a shootout of all orange bikes), one thing became very clear: KTM is absolutely focused on raising the two-wheel bar each year. In many ways, they’ve forced the Japanese and other manufacturers to rethink their product cycles and adopt new technology to keep up, which is great for all of us in the long run. It’s hard to go wrong with any new motocross bike these days, but with an entirely all-new lineup from KTM, the folks from Austria are doing their best to make that choice a little easier.CN

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