KTM delivered the new 450SX Factory Edition to us last week. The bike was announced two months ago, which is enough time for the factory to homologate the bike for the supercross season, This is the basis for the bike that Ryan Dungey is using to lead the points in the 2015 Monster Energy Supercross season, and it’s all new. We mean ALL new.
Almost all elements of the redesign were aimed at weight reduction. The engine is 23mm shorter in length, 23mm narrower and 9mm shorter in height. KTM also moved the crank rearward 9mm and upward 7mm in an effort to centralize mass. The crank itself is new and has more inertia without gaining weight, presumably through an increase in diameter. The gears in the five-speed transmission have the same ratios as the standard 2015 model, but have material cut away for less weight. The clutch is still a DDS design with a diaphragm spring, but it has been reworked and sits above the oil bath for less drag. It uses oil jets for cooling and lubrication.
There are three different fuel/ignition advance maps programmed in the bike as delivered, and more can be added with KTM’s laptop-based User Setting Tool. You can switch between the standard map and any other one of your choosing via a handlebar switch. Additionally, there’s a launch control map available, although our test bike was a very early production unit and didn’t yet have that function programmed in. Check back later on www.dirtbikemagazine.com for a report on how it works. The throttle body itself is new, but still has the injector on the bottom and measures 44mm. It’s mainly smaller, lighter and eliminates some parts.
As you might expect, the exhaust, head, cylinder and piston have been redesigned. The
cylinder itself accounts for most of the engine’s reduction in height. The starter was redesigned and is now driven by a Samsung lithium battery, which accounts for 2.2 pounds of the weight loss. The steel frame is supposed to be 380g lighter but with more torsional rigidity and less longitudinal stiffness. The subframe is new, the swingarm is new and the airbox is new, all said to be lighter. The rear shock has a smaller shaft and shorter overall length. Despite that, new linkage results in 10mm more suspension travel. The 4CS fork looks the same, but has settings that were developed mostly in the U.S.
So what’s the bottom line for all the weight loss? KTM’s claim of a 10-pound reduction is accurate. On the devastatingly accurate Dirt Bike scale, the standard 450SX-F is 238 pounds without fuel. The Factory Edition is 228. To put that in perspective, the next-lightest 450 is the Honda CRF450R, at 234 pounds, and it doesn’t have electric start.
On the track, the Factory Edition is better in every way. Let’s start with the power. The new bike has much less engine drag. It barks. With the ignition set to the standard map, it pulls wickedly hard in the middle, and it doesn’t taper off on top as much as the old motor. It goes all the way up to 11,500 rpm, and is usable all the way. On top it’s better to shift, but you don’t have to. It will keep going and going.
If you’re young and strong, there’s nothing wrong with the aggressive map. Just be prepared for faster response and more of a hard-edged bark at smaller throttle openings. The mild curve takes away some of the bite down low and makes you twist the throttle farther. To confess, we didn’t ride with the mild curve very long. We know it’s probably more efficient, but the bike is much more fun when it’s in its nastier moods. The mild curve also makes the gears feel more spread out because the powerband isn’t quite as wide. You actually find yourself using the clutch to make up the gap. The clutch, by the way, is excellent. It has a light pull, precise engagement and doesn’t drag.
The weight loss is as impressive as the horsepower gain. That much weight loss can be felt by anyone. The bike feels lighter in the air, lighter in turns and lighter when you put it on the stand. We aren’t ready to say it feels lighter than the Honda, though. The sensation of mass comes from other factors, too. Horsepower makes a bike feel heavy, and the KTM has much more peak power than the Honda CRF450R. So, yes, the KTM feels light because it is light. But you still have to renew your gym membership if you want to toss it around.
If you’ve been paying attention, you know that suspension was never the KTM’s strong point. We know that KTM did a lot of testing here in the U.S. Mike Sleeter was out at Glen Helen every week, working with the WP guys. We’re pleased with the results. The fork has a much higher comfort factor than ever before. In our experience, the 4CS fork is harsh and cruel unless it’s set up very soft. In general, that makes it unacceptable for higher speeds and rougher tracks. For the Factory Edition, the settings that KTM came up with are surprisingly good. Fast guys will still say the fork is too soft and slow guys will say it’s too stiff. But it’s in the hunt. It’s still not the best front suspension in the game. It’s just better than it was.
The improvement up front is big enough that some riders will turn their main focus to the rear. That’s human nature. The rear end is still pretty good, although no one would call it plush. With the reduction in overall weight, it has less work to do. The bike is so light that getting a little sideways in the whoops is no big deal. The lighter weight makes it easy to recover from mistakes or really bad sections. You still feel the bumps, but nothing gets scary. We set up the bike with around 105mm of sag. You can go quite a bit higher or lower than that if you like because the rear end has more travel, and that makes it more forgiving of sloppy set up.
KTM clan members will probably say the new bike feels nothing like the old one. That’s because the ergos that have defined KTM motocross bikes for years have been drastically altered. Yet, the bike still handles in much the same way, with the same strong points and weak points. The footpegs are mounted more rearward, and both the handlebar and seat are lower. You would think that those things would make the bike more cramped, but that’s not the case. If anything, the Factory Edition feels roomier. The seat shape and the flat junction to the fuel tank make it easy to move around. The seat is very narrow, but softer and more comfortable than past KTMs. All that will make it more appealing to riders who usually don’t drink the KTM Koolaid
The anti-KTM crowd has very little ammunition in this bike. Just look at the number of “bests” here: The 2015 Factory Edition has the most power, the lightest weight, the only electric starter, the best brakes and the best clutch. All of that is undeniable. Will you be able to buy one? Probably. Dealers who move more motocross bikes will have first shot, and even though most of them have had customer deposits since December, there are invariably bikes that become available. The price: $10,199.