Yamaha isn’t being subtle about it anymore. This is war, and the stakes are nothing less than ownership of American soil. The Yamaha YZ450FX is a 450cc off-road racer without compromise. It’s not made for trail riding. It’s not made to pass EPA emissions tests. It’s not made to be soft-spoken or even nice. This is a bike made with off-road performance as its one and only priority. If that description sounds familiar, it’s because it was taken directly from KTM’s playbook. The 450XC-F was made with exactly the same mission. Yamaha knows it. KTM knows it. And so do the off-road riders in America who have been calling for this bike.
KTM makes a lot of dirt bikes. The 450XC-F has been the king of off-road racing in America for years. It has won championships in National Hare and Hound, GNCC, WORCS, desert and cross-country. KTM envisioned the bike as a racer right from the start, making it one of the few bikes that can be taken directly to the starting line of a national championship off-road race without modification. American racers aren’t used to that. We usually start with either a motocross bike or a trail bike, and then go to work re-valving, re-gearing and refitting it with the proper equipment. The 450XC-F is akin to the 450SX motocrosser; in fact, it has the same motor with a wide-ratio gearbox. It also has a larger tank, a kickstand, an 18-inch rear wheel, handguards and softer suspension. The picture is clouded somewhat by KTM’s other 450 off-road bike, the 450XCF-W. That bike is softer, quieter, cleaner and less racy. That’s not the bike we have here.
For 2016 the 450XC-F is almost completely new, just like the motocross version. KTM stuck with the same layout (a single-overhead-cam, four-valve motor), but changed every part. The what-and-why list goes on and on and can be found at
www.dirtbikemagazine.com (search “First Look: KTM’s 2016 SX Models”). The reason behind all the new part numbers was weight reduction. The motor is physically smaller too. It’s 23mm shorter from front to rear, 9mm shorter in height and 9mm narrower. And, the crank has a 10-percent increase in inertia without an increase in weight. The radiators, pipe, footpegs and shifter are all new. The frame was redesigned with weight loss in mind, too, and the bike got a lithium battery.
The list of stuff that isn’t new is much shorter. The brakes, wheels and suspension components are essentially the same units, although the WP fork and shock did get new valving.
Until last year, Yamaha’s off-road bikes have been of the soft, quiet, clean and less-racy variety. The WR450F was extremely quiet, almost to the point of silliness. It had a throttle stop that only allowed half throttle, among other odd restrictors, and was fully compliant with EPA and CARB emission requirements. The WR will still exist in the Yamaha line, but now it coexists with this closed-course, competition version, just like KTM’s. And like KTM, Yamaha used its motocross 450 as a starting point for the new model. In this case the conversion was more difficult, because the MX bike doesn’t have electric start. Yamaha redesigned the left side of the engine case to accept a starter motor, then beefed up the generator and added a lead-acid battery.
Every ratio in the five-speed gearbox has changed, with first and second moving dramatically lower. Fifth is only slightly taller than on the MX bike. Yamaha reworked the clutch and radiators to deal with greater heat and altered the EFI mapping to tune the power delivery for off-road use. The motor is still somewhat outlandish, just like the MXer’s. The oddly angled head is backwards, with the exhaust in the rear and the intake in front. That puts the injection and the airbox up front and very high, about where the gas cap is on a conventional bike. The Yamaha’s gas cap is now located under a pad at the front of the seat.
As you might expect of an off-road bike, the rear wheel is an 18-incher. There’s a kickstand, and the suspension is softer than that of the MX bike.
Yamaha deviated from KTM’s formula in a number of ways. The YZ450FX uses the same fuel tank as the motocross bike, which means it holds 1.9 gallons and is a 1/2-gallon smaller than the KTM’s. It doesn’t have handguards (the KTM does), but it does have a skid plate (the KTM doesn’t). The Yamaha has a cable-operated clutch, whereas the KTM’s is hydraulic.
The most startling difference between the two bikes is weight. KTM was phenomenally successful in its mission to shed weight. The 2016 450XC-F checks in on the fabulous Dirt Bike Super Scale at 230 pounds without fuel. The Yamaha weighs 253 pounds without fuel. Why the weight difference? Part of it has to do with the price. The KTM sells for $9999, while the Yamaha is $8890. That additional $1109 allows KTM to buy into pricey things like lithium batteries. But, you still have to give KTM’s engineers credit for a job well done.
These are two incredibly powerful motorcycles. They give up absolutely nothing to their motocross counterparts, which have, by the way, the two most powerful motors in the MX world. The KTM and Yamaha 450s feel even more over-the-top when you put them in an off-road environment. You only need this much horsepower about 2 percent of the time—maybe on a wide-open desert sand wash or on a steep, straight hill. But, man, is it fun to open the throttle when you have the opportunity!
In absolute peak power, the two are more or less equal—both are so far over the top that it’s actually irrelevant which makes the biggest number. But, they have very different power characteristics. The Yamaha hits much harder. Way down on the bottom it has a hint of that on-or-off jerkiness that has always been present on fuel-injected YZ motocross models. Then, in the middle of the powerband, the output goes from massive to extreme very quickly. Precise throttle control is the key with the Yamaha. The KTM’s power delivery is much smoother. It still makes so much power that a careful right hand is essential, but the steep part of the powerband is more spread out. The KTM catches up by revving higher than the YZ, although it takes a very determined rider to actually reach the rev limiter on either bike. Down low the KTM doesn’t have as much of the on-or-off feel, but it will cough and die occasionally.
When you find yourself on a tight trail, several things become apparent. First, the Yamaha is geared lower. First is so low that you’re better off pretending it’s not there until you absolutely need it. In extreme circumstances, it’s a pleasant surprise to find that you have another gear. On the same trail where you ride the Yamaha in second and third, you ride the KTM in first and second. When it gets really tight, the KTM runs much hotter than the Yamaha. It’s not hard to boil the KTM. We got both bikes stuck a number of times but never boiled the Yamaha.
TRACK AND TRAIL
No one knows exactly where these bikes will be ridden. They could end up anywhere from eastern mud trails to western motocross tracks. Both companies simply had to make a guess when it came to suspension setup. The KTM is stiffer, designed more for GP tracks out west. It’s just a little softer than a full motocross bike. In fact, we had many riders say they would have no problem using the XC for motocross without modification. Funny, we never hear that about KTM’s motocross bikes. The truth is, the WP 4CS fork works best when it’s set up somewhat soft, and that’s exactly what the XC is: a soft MX bike.
Yamaha aimed the YZ450FX more toward trail use. It’s softer than the KTM and much, much softer than the YZ450F motocross bike. The fork is excellent for rocks and roots, particularly at lower speeds. When you get into big whoops, the front end is a little too soft, and the whole bike moves around somewhat. The rear, on the other hand, is stiff enough to handle anything from whoops to MX jumps. Depending on where you ride, you’ll either want to soften the rear or stiffen the front. Either way, the Yamaha’s suspension has its work cut out for it. The bike is overweight. It’s not crippling, but it is noticeable. When you descend on steep hills, the weight takes over and the soft fork doesn’t help.
Both bike have strengths and weaknesses. The KTM is smoother, lighter and more well-balanced. The Yamaha is snappier, plusher, runs cooler and has a granny gear for really tight spots. There are certain areas where we thought the KTM would have a clear advantage, but the Yamaha surprised us and came out smiling. The clutch is one of those. We thought the KTM’s hydraulics would be a clear advantage, but the Yamaha’s old-school, cable-operated clutch had excellent feel and a lighter pull. The Yamaha’s Nissin brakes were also surprisingly good and capable of going toe to toe with the KTM’s Brembos. Overall, though, the KTM is a little more refined for off-road use, both on the track and trail. It’s an incredible bike and is at the very leading edge of technology. Yamaha already upset the status quo last year with the incredible YZ250FX, which was voted the best in its class. Apparently, KTM was determined not to let that happen again.