How Do The New Chassis & Engine Changes Of The 2019 KTM 450 SX-F Feel On The Track?
Photos by Donn Maeda
Video by Casey Davis
When KTM released its all-new 2018 450 SX-F Factory Edition late last year, the all-new chassis, updated suspension, revised powerplant, and new bodywork made the standard 450 SX-F seem ancient in comparison. The new machine handled better, had snappier throttle response, and had a slimmer, sleeker feel between the rider's legs. For 2019, the standard 450 SX-F got all of that technology, plus some slightly updated suspension settings: the only thing that's missing are Red Bull graphics and a Selle Della Valla seat cover!
Nothing is changed as far as the 450 SX-F powerplant goes, and that's a good thing: the big orange machine is an absolute monster when it comes to putting our massive amounts of torque throughout the powerband in a smooth, easy-to-manage manner. The bike still boasts two ignition map setting that are adjustable on the fly (standard and aggressive), as well as traction control settings that work in both maps.
To the untrained eye, the frame itself looks identical to that found on last year's standard model, save for new black paint, but reworked mounts, cross members and tubing result in a chassis that has more torsional rigidity for greater steering precision and bump absorption. Adding to the more-precise front end is a new triple clamp that is beefier in the front sections for added rigidity and control. The clamp boasts two different bar positions. Out back, the aluminum subframe is 40 mm longer, and the swingarm's range of adjustment was lengthened by 5 mm, giving you the ability to stretch out the bike's wheelbase with more-rearward wheel positioning.
Both ends of the WP suspension receive updates internal settings for improved comfort and control, though no major revisions were required by the new chassis as the bike's dimensions and leverage points remain the same. The left fork, which controls the air spring, received a spacer in the negative air chamber that reduces volume by 50% for more responsive action in the initial parts of the stroke. Out back, a new main piston and revised valve settings in the shock are tuned to complement the front end and maintain excellent balance.
Of course, the all-new bodywork gives the bike a subtle, but excellent facelift. New plastics are narrower between the rider's legs, and a longer seat offers more room for maneuvering in comfort. The seat cover features modest silicone ribs for improved traction under acceleration.
On The Track
Though we have already ridden last year's Factory Edition plenty, it's in comparison to last year's standard machine that the 2019 bike is noticeably slimmer and easier to maneuver on. The new bodywork is much more comfortable, and the wide point at the radiators seems to have been tucked in a little better.
The greater rigidity of new chassis allows the bike to steer superbly, as the machine goes exactly where you point it, with minimal wander. The more-rigid triple clamp adds even more precision to the traditional razor-sharp handling of the KTM, and we found that the standard rearward bar mount position was comfortable for all of our testers. The stiffer feel of the chassis is much appreciated in high-speed as the bike absorbs the impacts from track imperfections and quick directional changes direction with precision, where the older chassis would sometimes flex and stand upright. Under braking, the bike has a much more positive feel and stays planted to the ground.
Suspension-wise, the KTM 450 SX-F is well balanced and easy to dial in. As we've said before, the WP AER48 is the best performing air fork; but that all four of the Japanese manufacturers have returned to the superior mechanical spring design, we wonder how long KTM will carry on with air. The appeal of air? The AER48 fork can be tuned to suit a wide range of riders with the simple addition or subtraction of air pressure. Suspension action on both ends is supple in small braking and acceleration chop, but the fork lacks some predictability as it travels through the middle of its stroke. We added a couple clicks of rebound dampening to slow the front end down a tad, and found that it made the bike much more trustworthy and even better balanced than before. Truth be told, we could not detect a difference in the suspension performance between last year's FE and this machine, although there were some small internal refinements.
When it comes to power, the KTM 450 SX-F powerplant can barely be faulted: it comes on strong down low, pulls massively in the mid-range, and rev out as far as most mortals would care to rev a 450. It delivers power in a smooth, predictable manner, yet it does so with so much torque and authority that it can be intimidating. The map one setting is the easier to control of the two, but map two is certainly exhilarating and makes things happen in a hurry. Advanced riders will enjoy the aggressive setting the most, while less experienced riders will love the traction control feature.
All told, the 2019 KTM 450 SX-F is every bit as excellent as the '18 Factory Edition machine was, and it is going to be a very interesting contest when it comes time to select a bike of the year in the 250 class.
2019 KTM 450 SX-F UPDATES & FEATURES
All-new frame design with focus on stiffness to improve handling and stability
Redesigned, lighter swingarm with additional 5mm of adjustment compared to predecessor
Revised bodywork and seat
Reworked airbox to improve flow of air through intake system
New fuel tank with improved ergonomics, 1.85L capacity, and revised hose routing
New model-specific exhaust system, featuring FDH resonator on the header pipe and easy to remove silencer
Revised ignition map settings
New lithium ion battery for electric starter system
Redesigned radiators for improved cooling
New main piston in the WP Monoshock
Revised setting in WP AER48 fork
Redesigned upper triple clamp for improved stability
New exhaust valve camshaft and timing
Reworked cylinder head for lighter weight
Diaphragm steel clutch system with one-piece basket and Brembo hydraulic actuation system
New Pankl five-speed transmission
Updated Keihin engine management system, including revised throttle body and optimized ignition maps