2020 KTM 350 SX-F First Ride Review

Relatively minor refinements make for much better performance on the track.

Glen Helen Raceway
Riding the 2020 KTM 350 SX-F at Glen Helen Raceway in San Bernardino, California.Mark Kariya

KTM's entire full-size motocross bike lineup received a host of engine, suspension, and chassis changes in 2019. The new generation motorcycles boasted a stiffer frame, but in turn, it lost some of the comfort it was once praised for. Also, the suspension settings were off and didn't complement the more rigid chassis. KTM put in the time to refine its suspension settings to better suit the latest-generation platform for 2020. It also found some additional power with a simple airbox modification. We headed out to Glen Helen Raceway in San Bernardino, California, to test the 2020 KTM 350 SX-F and came away impressed with the refinements the Austrian manufacturer made to its midsize motocross bike for 2020.

2020 KTM 350 SX-F Engine

Although there weren’t any updates made to the 350 SX-F engine itself, it surprisingly feels like it runs a little better than the 2019 model. This could be attributed to factors such as the suspension settings and optional vented airbox cover.

Describing the engine’s power is somewhat difficult. You have to keep the rpm up a little higher than a 450, but nothing like a 250F. The roll-on power is good, and if you are in the correct gear, it does not require much clutch input. The 350 SX-F doesn’t quite have the grunt of a 450 to pull you out of a mistake, such as sinking the bike into a deep berm, but it is a little more forgiving on a flat corner if you grab too much throttle. The midrange power is excellent and keeps building all the way to the rev limiter. If I had to categorize this engine, I would put it more in the 250F category because of its midrange and high-rpm power.

It took a few more laps than expected to get familiarized with the engine’s power. Since I have been riding a 450 the past few weeks, my tendency was to ride lower in the rpm. I found myself upshifting a little too soon and not downshifting enough in corners. Once I readjusted my gear selection and learned exactly how far the 350 SX-F could rev, it became more natural. As for the engine and powerband, I would describe it as the world’s fastest 250F. If you love a 250F power and simply want more of that characteristic, this is the bike for you. If you ride lower in the rpm and are a point-and-shoot type of rider, you might be a little disappointed.

Of the two available maps, I ran the bike in map 2, which seems to be my preference on most KTMs. It has increased torque in comparison to map 1, which aids the bike’s ability to carry third gear. The traction control (TC) option is good, but it takes a few laps to learn just how it is really helping because it’s not all that noticeable when first turning it on. It’s more significant when you have been riding with it on and then turn it off later in a moto. I rode with it on for several laps and didn’t really think it was doing much, so I turned it off. After two laps, it was more apparent that it really helped with wheelspin and corner exit control. With TC off, the rear wheel lost traction a few times in an area where I didn’t have that problem when TC was on.

The optional black throttle cam and vented airbox are also notable improvements for a serious motocross racer. The black throttle cam helps reduce the KTM’s long throttle pull (in comparison to some of the other bikes) to a more comfortable position. The optional vented airbox cover on the 350 SX-F offers a more noticeable difference than it does on the 450 SX-F. It’s like going from pump gas to high-end race gas. It added power across the entire rpm range and made it feel like it just wanted to rev to the moon. I seriously tried to find the rev limiter a few times, but assuming I came out of most corners in the correct gear, it was almost impossible to reach.

The gear ratios on the 350 SX-F are good. It took me a few laps to become more acclimated to the powerband and be in the correct gear. I found it a little bit difficult to upshift under load, especially going uphill. I either had to let off the throttle more than I wanted or use the clutch more than expected, and sometimes both. In a racing scenario, if you are alongside another rider or have someone on your rear fender, this could allow them a slight advantage.

KTM 350 SX-F
After receiving a bevy of updates in 2019, the KTM 350 SX-F features a couple of minor changes for 2020, one of which is that the WP Xact suspension components have revised settings.Mark Kariya

2020 KTM 350 SX-F Suspension

For 2020, the new WP Xact suspension settings are a significant improvement in comfort and overall performance. KTM’s efforts in this area are noticeable and praiseworthy. There is an increased plush feeling in both units while still retaining the positive feeling of the frame and triple clamps. I found the bike much easier to set up for my riding style and ability. I was able to set the shock ride height a touch higher than recommended to help with cornering and offset the slightly high front end sensation due to the air fork’s tendency to ride high in the stroke. Since my preference on previous SX-F models has been uniform, I raised the fork in the triple clamps from the stock second line to the third line to add more weight on the front wheel.

After a few motos, I was getting comfortable and started to feel like the bike was a little too low in the front, so I increased the air pressure from the stock 10.4 bar to 10.7 bar and stiffened the compression three clicks. This helped with front end comfort under braking and it didn’t negatively affect the bike’s cornering ability. This allowed me to ride even farther forward on the bike. My final adjustment was to slow the rebound damping by two clicks front and rear.

350 SX-F
Like the 250 SX-F and 450 SX-F, the 350 SX-F comes with an optional vented airbox cover for 2020.Mark Kariya

2020 KTM 350 SX-F Chassis/Handling

With the way I was able to set up the 350 SX-F, it is the best turning KTM I have ever ridden. It wants to stand up a little more than I would like in corners, but with some additional time getting to know the bike and a few more small adjustments, I could improve on that. While you need to ride the 350 SX-F a little more like a 250F, there is a little more noticeable weight to it in comparison to a 250F because of the larger-displacement engine. However, it still has a lighter feeling than a 450.

vented airbox
The new vented airbox cover works. It’s like going from pump gas to high-end race gas with added power across the entire rpm range.Mark Kariya

The KTM’s cockpit is comfortable with its flat seating position from front to back and its sitting on top of the bike feeling, both of which help make it easy to move forward at corner entry. The Brembo front brake seemed to offer good initial bite, but it was not progressive enough on higher-speed, heavy-load stopping. After a long, fast, high-rpm fourth-gear section into a tight 90-degree corner, I would have liked a little more stopping power up front. The rear brake is great and easy to modulate; KTM’s smaller 220mm rear rotor does not lock up the rear wheel as easily as some of its competition.

350 SX-F on a jump
The suspension settings on the 350 SX-F are dramatically better than 2019. It has by far the best WP air fork we have ridden with.Mark Kariya

The more I rode the bike, the better it felt. With consideration of the track conditions at Glen Helen being higher speed and choppy, I would say the bike is confidence inspiring. Our testbike was still quite new as we started the day with only two hours on the meter. The rigid frame and triple clamps were still noticeable, but I think the stiff feeling may decrease as the bike breaks in more. I would really like to make a comparison at the 15- to 20-hour mark to see if some or all of the rigid feeling goes away.

350 SX-F wheelie
Like the 2019 model, the 350 SX-F chassis is still a little stiff, but it might improve after the bike continues to break in and has 10 or more hours on it.Mark Kariya

Overall Impression

If you are an all-round rider or racer regardless of whether you ride motocross, off-road, or trails, the KTM 350 SX-F should be a serious consideration when making your purchasing decision. If you are a pure motocross racer and are set on racing a class defined by engine displacement, you might want to stick to a 250F so you can enter multiple classes (250 and Open) on race days.

350 SX-F ride
With more power than a 250F and without the fatigue that sometimes comes with riding a 450, the 350 SX-F is an excellent option for those looking for something in the middle.Mark Kariya

Gearbox

TECH SPEC

PRICE $9,799
ENGINE 349.7cc, liquid-cooled, single-cylinder four-stroke
TRANSMISSION/FINAL DRIVE 5-speed/chain
MEASURED HORSEPOWER N/A
MEASURED TORQUE N/A
FRAME Steel central double cradle
FRONT SUSPENSION WP Xact 48mm fork adjustable for air pressure, compression damping, and rebound damping; 12.2-in. travel
REAR SUSPENSION WP Xact shock adjustable for spring preload, high-/low-speed compression damping, and rebound damping; 11.8-in. travel
FRONT BRAKE Brembo 2-piston caliper, 260mm disc
REAR BRAKE Brembo 1-piston caliper, 220mm disc
WHEELBASE 58.5 in.
SEAT HEIGHT 37.4 in.
FUEL CAPACITY 1.9 gal.
CLAIMED WEIGHT 219.4  lb. (w/ all fluids except fuel)
AVAILABLE Now
CONTACT ktm.com