KTM has led motocross development for several years, offering some of the lightest and fastest “ready-to-race” showroom stockers on the planet. With the introduction of the 2018½ KTM 450 SX-F Factory Edition, the Austrian bike maker has demonstrated it has no intention of relinquishing its place at the front of the field.
What is a “factory edition” and why does KTM produce it? To satisfy AMA competition rules, racebikes are required to use major production components—engine cases, cylinder, head, frame, and transmission. The Factory Edition exists for one reason: to meet the minimum 400 units required for homologation.
At first glance, the 450 SX-F FE doesn’t look that much different than its predecessor, but it is a new bike. This is in contrast to the ’17½ and ’16½ FEs, which were mostly updates to the then-current models. Subtle changes to the bodywork conceal a 15mm-lower cylinder head and an all-new frame with a 40mm-longer subframe.
That new frame is said to be longitudinally stiffer to improve bump absorption, stability, and rider feedback and is complemented by CNC-machined 22mm-offset triple clamps. A rubber damping system reduces vibration through the handlebar to improve rider comfort. Suspension remains the same WP components, with the shock getting a new piston and both ends receiving revised valving.
While it’s not immediately obvious, the rear of the bike is also new. The fender, seat, side panels, and radiator shrouds were reshaped to offer greater rider maneuverability. Similarly, the gas tank sits lower in the frame, providing a flatter seating surface, with what appears to be a thicker piece of foam.
Radiators are a necessary evil on modern bikes. KTM has redesigned and relocated the radiators to improve ergonomics and handling. The CFD-designed cooling system is thinner, lower and pushed back, all of which moves weight more between the rider’s legs and improves mass centralization.
A longer cast aluminum swingarm completes the changes to the updated chassis. The added length comes at the end of the arm in the form of an additional 5mm of axle positioning. If you like the feeling of a short wheelbase, don’t worry: You don’t have to run your rear wheel 5mm farther back, but you certainly have the option.
KTM continued with updates to the electronics, fine tuning the placement and weight of those components. A new-generation 2Ah lithium-ion battery is even lighter than the already ultra-light unit that comes on the standard 450 SX-F. The capacitor and voltage regulator were relocated under the seat, alongside the ECU, further centralizing mass.
Access to those electronics is improved via an easy-to-remove seat. A new single-bolt release is now located on the side of the bike, not under the rear fender where in the past you had to deal with dirt and mud whenever you wanted to take off the seat.
Engineers redesigned the four-valve, SOHC cylinder head, which is visibly more compact. The camshaft is now located closer to the bike’s overall center of gravity, further improving mass centralization. Intake and exhaust ports are now straighter for better airflow, which KTM claims has improved horsepower output. And though the cam lobes are the same profiles, the intake has been advanced two degrees; this change likely means an increase in bottom end power.
Another benefit of the new head is that the throttle-body position has changed, making it easier to service the cables. To improve durability, the transmission is now manufactured by Pankl with, according to KTM, “optimized design, material, and heat treatment.” The entire engine is said to weigh one pound less than before.
The exhaust system also has been revamped. The header has a flow-designed resonance chamber, and the hydro-formed mid-pipe has an oblong shape. It is now possible to remove the header and muffler without first removing the shock. The new muffler is shorter and more compact to, once again, bring weight closer to center of gravity.
They say good things come to those who wait. Unless your name is Marvin Musquin, Brock Tickle, or you ride for a KTM factory-supported Supercross team, you probably won’t get to swing a leg over one of these bikes until next April. Be sure to have your cash ready; with only a limited quantity available, they won’t last long.