With the introduction of the brand-new YZ450FX, Yamaha pretty much plugged up any hole it might’ve had in its off-road lineup. Yamaha already had the YZ250FX and WR250F four-strokes, and the YZ250X two-stroke in its arsenal, and now it has the big gun, the YZ450FX. No other Japanese manufacturer has so many off-road bikes its lineup to choose from. Not even close.
You can read the original magazine story by clicking HERE.
What Is The YZ450X?
Like all of Yamaha’s competition off-road bikes before it, the YZ450FX is based on its YZ (motocross) cousin, in this case the 2016 YZ450F (we’ll refer to it as simply the “YZ” in this report). The FX is essentially the same motorcycle but with many key changes that address the specific needs of the off-road racer, which is no different than what Yamaha has done with its YZ250FX and YZ250X models. And like all of its FX brothers, the YZ450FX is deemed a full-on race bike strictly intended for closed-course competition; therefore it doesn’t fall under the same EPA and CARB umbrella as your traditional trail/play bike, or any motorcycle intended to be ridden on public land. This is what the new 2016 WR450F is for. (The all-new green-sticker WR450F has just been released and should start hitting showroom floors as we speak. We just got ours, and we’ll talk about it very soon in an upcoming issue.) Yes, the YZ450X is, like a motocross bike, 100-percent pure race, specifically designed for GNCC and grand prix-style competition. Honda, Suzuki and Kawasaki have no such animal(s) in their war chest these days.
Again, there are several notable differences between the YZ450F and YZ450FX. The most significant and perhaps most welcomed is the addition of push-button electric starting, which required a redesign of the left engine case and left-side crankshaft, the addition of a battery, and a stronger generator. Output is bumped up significantly, from 95 watts to 160 watts, and flywheel inertia has been increased two percent to smooth out power delivery. To reduce vibes, Yamaha says that 100 percent of the reciprocating weight is now balanced by the counter-balancer, whereas on the YZ-F, it’s 88 percent.
Another major difference is the gearbox. Ideally, an additional sixth gear would’ve been added, but since that’s not feasible, Yamaha went to great lengths finding the ideal blend of internal (and external) gear ratios for the FX’s now wide-ratio five-speed transmission. What they came up with was a lower first gear that would require a 14-tooth larger rear sprocket on the YZ450F to get the same effect (both bikes are fitted with a 13-tooth countershaft sprocket; 48T in the rear for the YZ and 50T for the FX). Second gear you’d need an eight-tooth larger rear sprocket, and third gear a two-tooth larger sprocket. Fourth gear is about the same overall as the YZ450F. Fifth gear, however, you’d need a four-tooth smaller rear sprocket on the YZ to get the same effect as the FX. According to Yamaha, this is about a 30 percent wider range than the YZ.
Yamaha didn’t forget about the clutch, either. It’s been beefed up to handle more abuse that off-road riding usually dishes out, and clutch pull was designed to be lighter, 10 percent lighter to be exact.
Since off-road races are generally run at a slower speeds (at times no speed at all!), not as much air flows through the radiators as compared to motocross, so that’s why Yamaha redesigned the FX’s radiators to capture more air. Compared to the YZ450F, the FX’s radiators are 30mm longer and the pitch of the radiator fins has increased half a millimeter; this allows more air to pass through the radiators at slower speeds. There is no radiator fan but there is a mount for one in case you want to install one later. The mounts are designed for the same fan unit that comes stock on the 2016 WR450F, so it will bolt right up.
Otherwise, the FX’s 449cc liquid-cooled four-valve DOHC four-stroke motor is the same as the YZ’s, which features its rearward-slanted cylinder design, with a reversed cylinder head and forward-positioned straight intake. Any performance changes were done electronically via a different ECU and different fuel-injection mapping. ECU tuning can be personalized via a GYTR Power Tuner, which is sold separately for $291.95 and can also be used on any fuel-injected YZ or FX model.
Suspension has been tinkered with, of course. However, it uses the same 48mm KYB Speed Sensitive System spring fork and shock as the YZ but with minor valving changes. The fork has lighter 4.5 N/mm springs versus the F’s 5.0 springs. Surprisingly, the shock spring is the same as the FX’s.
It goes without saying that the FX is fitted with an 18-inch rear wheel, which allows for a taller tire sidewall that better absorbs the rocks (for a smoother ride) and is less susceptible to pinching (flats) than 19-inch wheels/tires. Cross-country-spec AT81 Dunlop tires are standard on the FX.
The FX is also fitted with a kickstand, an O-ring chain, a skid plate, but no handguards or oversize fuel tank. The stock tank holds 2.0 gallons, same as the YZ450F.
MSRP is $8890, which is about $300 more than the YZ450F, but the electric starting and wide-ratio transmission are worth their weight in gold. The 2016 KTM 450 XC-F, a comparable bike that quickly comes to mind, sells for $9999.
Close your eyes, climb aboard and you wouldn’t know which bike you are on. The YZ and the FX have the exact same ergos. Feel around the right handlebar, though, bump the button, and when the bike suddenly comes to life, you’ll quickly know that you’re on the FX. It starts that easily. The FX’s starter is strong and quickly brings the bike to life, and we later found that to also be the case with a hot motor and the bike still in gear.
The YZ450F is a fantastic motocross bike. For the second straight year, in fact, it was the top dog in our 2016 MX shootout, but this bike is a monster on the trail, so we were quite surprised by how well the FX behaved the first time we got it on the single-track. All those changes Yamaha made to it certainly made a difference and all for the good.
The FX, however, is still a beast, there’s no getting around that; after all, it started out life as one of the most powerful bikes in motocross, but it’s now a much more tamable beast. Power delivery is far smoother than the YZ’s and a lot more usable, which is what you want when you’re threading the needle on a tight, zig-zaggy, single-track trail that offers no room for error.
First gear is very low and extremely useful in the ultra-tight stuff, but second and third gears are the ones you’ll be spending the most time in. Second is quite low and will do a lot of the work that first gear would normally be doing, but since there is so much bottom-end power and torque, you really don’t need to visit first gear all that often—just leave it in second and life will usually be good. This is also nice because it cuts down on the actual process of changing gears by the rider, so less energy is being spent. Third gear is probably the most useful on the FX; it’s plenty wide and makes it easy to keep your momentum up on the twisties and while climbing long hills. Fourth and fifth gears are reserved for the really wide-open stuff. And, yes, this bike is very, very fast. Is anyone surprised?
But most of our time so far on the FX has been spent in the slow-going stuff (compared to MX that is) and we’re impressed by how well the Yamaha handles the crawling speeds. You can just leave it in a tall gear and let the motor do most of the work while you concentrate on the important things like just having fun. The clutch is very strong and never completely lost its poise when things got warm, nor did our bike ever turn into a geyser. (But we have yet ridden it on a 90°-plus day.) The FX rarely stalls, but when it does, it’s usually rider error and not the fault of the bike. And, like we already said, just hit the switch and it fires right back up before you even roll to a stop. Yamaha was smart enough to leave the manual kickstarter for back up, just case the electrics go haywire. Thank guys.
Suspension is very good right out of the crate. It definitely feels plusher overall than the YZ’s suspension, though heavier riders might feel that the front end is a little too soft. Easy fix, though. There is plenty of adjusting abilities with those awesome KYB SSS forks, which just might be the best fork in the business.
The FX is a solid-handling machine and really doesn’t take a lot of muscle to make it do what you want it to do. However, in general, the FX is a big-feeling bike and it’s, well, unfortunately, very heavy. It’s about 15 pounds heavier than the YZ450F and that’s not good news for the FX, since the F is already one of the heaviest bikes in its class. And it gets worse. The KTM 450 XC-F is a good 20 pounds lighter (and trimmer) than the FX! We found that as easy as the FX is to ride, it’ll still wear you out because of its sheer weight and bulk, and let’s face it, the FX is a powerful motorcycle and still requires some muscle and endurance no matter what, especially if you plan on riding the FX for any length of time on challenging trails. Luckily (well, that one way of looking at it), the small-ish gas tank will force you into pits more often for a quick breather. We say “small-ish” because it still holds two gallons, which is more than any other 450 MX bike; the KTM 450 XC-F, however, holds 2.2 gallons.
Despite its weight and size, the FX is still really fun to ride and is surprisingly easy to control on the trail, and even on the MX track. Yeah, it might be a little on the hefty side, but the FX makes a great practice-day motocross bike. Heck, we wouldn’t even hesitate to line it up behind the gate just to get our MX fix every once in a while. Beside, passing your friends on a bike with a kickstand is always gratifying, and this bike can do some passing.
Overall, we love this motorcycle and appreciate Yamaha not forgetting about the off-road enthusiasts and developing bikes like the YZ450FX and the other eight bikes in its off-road fleet.
SPECIFICATIONS: 2016 YAHAMA YZ450FX
Liquid-cooled, 4-valve, DOHC, single-cylinder four-stroke
BORE X STROKE:
97.0 x 60.8mm
Yamaha Fuel Injection (YFI) Keihin 44mm
TCI (Transistor Controlled Ignition)
Bilateral beam aluminum frame
KYB Speed Sensitive System (SSS), spring fork, fully adjustable, 12.2 inches travel
KYB, single shock, fully adjustable, 12.5 inches travel
Single 270mm disc
Single 245mm disc
Dunlop AT81F 90/90-21
Dunlop AT81 120/90-18
CLAIMED WEIGHT (wet):
30 Day (Limited Factory Warranty)
Team Yamaha Blue/White
You can read the original magazine story by clicking HERE.