2016 Yamaha YZ450FX

Introduction

• The full-sized Yamaha FX is here.
• Full-powered with proper setup for off-road racing.

Yamaha has recently had a big push into the competition off-road (non-motocross) segment of the dirt bike market. It isn’t surprising nor is it without reason. One look at KTM’s market share here and the growth of this segment makes it an obvious decision. But it isn’t as easy as putting softer suspension on your motocross bike.

The standard and class leading KTM XC is the target. The Orange brand has systematically developed their bikes to not only allow an XC version, the XC may be the bike driving the whole push in development. When they release the brand new SX and XC at the same time and not a year after the SX it shows how important this segment has become. And how much tweaking to the actual platform the do to make an XC perfect for a wide ranging duty call. And in Yamaha’s case it wasn’t as simple as “just copying” the XC platform.

Changes

• Wide-ratio transmission.
• XC-Spec suspension settings.
• Off-road tuned power.
• The usual off-road goodies.

The YZ450FX was not as surprising as it should have been. With Yamaha releasing the YZ250FX and WR250F a year ago the inclusion of a full-sized FX was just a matter of time. It is a very well thought out set of changes to the 2016 YZ motocross bike that worked wonders on the transition of the 250F. The two big changes, upgrades that would be extremely difficult or impossible for someone to do on their own are the five-speed Wide‐Ratio transmission which is 30% wider than the motocross transmission and the electric starting. Yamaha developed what they call an off‐road spec clutch pack that uses different plate materials and lighter springs for a better lever feel and a smoother engagement during hard use. Of course a large capacity generator is needed inside the ignition cover and a YZ450FX specific ECU is used to not only provide spark and fuel information but also power a fan if needed. The ECU also can make use of the GYTR Power Tuner which is one of the easiest to use and effective engine tuning tools we have ever used.

The obvious changes to an off-road bike are the 18” rear wheel, a skid plate (which was oddly missing from the YZ250FX), an O‐Ring Chain, an aluminum Side stand and suspension tuned for the job. A big difference from YZ motocross bike is the return of the 22mm off-set triple clamp and the use of a slightly longer shock length to raise up the rear of the bike. Yamaha went a little extra and tuned the engine mounts to a thinner thickness (from 8mm to 6mm) to allow some additional flex between the chassis and engine.  On the suspension the front fork spring is a rate lighter but the rear shock spring stays the same as the motocross bike. Internally there is a different valving setup that Yamaha refers to as XC spec.

And the rest of the bike is YZ motocrosser right down to the smallish fuel tank (2.0-gallons) and lack of handguards, which they do not call attention to. This FX is not a year behind or using old parts (unless you count the triple-clamp, but we see that as an advantage) as it is based off the very revised 2016 YZ450F and that is a good thing. We slapped some handguards on the bike and rode the wheels off it.

Power

• Nearly the same as YZ motocross bike except for the electric-starting stuff.
• The ECU controls all the power changes, you can easily have more.
• Aggressive as delivered, tunable in seconds.

If you know your motocross bikes then you know the YZ is a powerhouse and one of the most responsive 450cc bikes you can get. The design of the engine with its reversed cylinder head and very straight intake tract are conducive to making a lot of power. It has a very light flywheel feel, quick revving with lots of snap and big top-end power numbers. Not the best for off-road. But even with that engine a rider could simply get a GYTR Power Tuner and tame the beast. So it is no surprise that Yamaha have a very potent powerplant on their hands and they know how to work with it. The engine is, for almost all purposes the same. Same throttle body, same head, cams, same piston and compression ratio. There are some differences in the crank to hold the larger flywheel and also to change the balance. They wanted some additional inertia on the crank but not much more mass.The balance shafts were also weighted heavier to cancel out all of the vibration as opposed to the YZ which is only balanced 88%.

First off the electric starting is awesome. The YZ pretty much fires right up and is ready to go even though the starter does make a characteristic high-pitched whine common to E-start Yamaha dirt bikes like the WR. The exhaust note is just like the YZ, barky but not too loud which means OK for the track but in real off-road you might want to look at quieter options. Riders noticed the clutch pull is light and the transmission was smooth shifting.

Now onto the power. We will call it aggressive off-road and it pretty much mirrors the character and style of the YZ motocrosser with just a touch of off-road drive-ability thrown in. Yamaha definitely did not want this to be a sissy off-road bike. The hit and snap of the throttle at low RPMs is very snappy and very abrupt, enough to easily lift the front wheel without using the clutch if you are in a low gear. It builds quickly and it builds with authority and builds and builds and builds to a far reaching top end scream that seems too far for a 450. In fact the power hardly tapers but it also does not go and hit the rev limiter either.

Stock and standard the YZ is actually more suited to a motocross track or some fast and flowing trails than it is tight and technical riding. You can ride the technical stuff and the secret is riding the bike a gear high as the power is tamed--then you have to be a little concerned with stalling. The motor is very reluctant to stall if there is any throttle applied at all, but at zero throttle or a little mis-timed throttle stalling can and will happen. Staying in lower gears the bike easily lights up the rear wheel and there is a fair amount of compression braking on decel. The YZ craves traction, luckily the chassis helps the motor get it.

The transmission does not really feel like a wide ratio box and we say that as a good thing. You can feel the gaps if you are very sensitive to it, but no one ever complained. Even when riding on the track. First gear is great and you will hardly ever use it except for technical sections that are tough enough to bottleneck. But when you do you can let the clutch out and crawl so much better than if you had a tall motocross first gear. Perfect for when you need it and you’ll never know it is there unless you accidentally shift into it.  Second through fourth jump rates as they should and even fifth isn’t that much of a gap. Our bike went 97 MPH on a dry lake and was a little gearing limited but not by much.

One of the pleasures of the YZ is the use of the GYTR Power Tuner. Every YZ owner should have one of these and learn what it is capable of doing. We were able to try some of the Yamaha testing teams suggested maps and we even built a few of our own to shift and alter the power for different rider preferences and conditions. It was simple to make a map that was mellower on the bottom and less aggressive which allowed riding in the proper gear with less jerkiness and more traction still not losing anything in the mid and upper power. In fact when you make the bottom and small throttle openings more mellow the mid and top feel even stronger and more powerful than they already are. You can even tweak the map to make the bike as responsive as the motocross bike and even a bit more if you desire. Yamaha hit a home run with this bike for its intended purpose and it can do plenty more with simple tuning.   

The radiator has tabs on it for a cooling fan which is a GYTR option but we never needed it on ourtesting which was all done in cooler winter times. Or maybe the tighter radiator fencing is really working that much better? Since it isn’t necessary to abuse the clutch, especially in low gears, the main source of heat is minimized. But in lots of tight riding without airflow a fan would be a good idea.

Suspension

• Yamaha has been right on target with their XC-spec.
• Stiff enough for motocross, soft enough for trails.

Yamaha has been on a roll lately in the praise they have been receiving for their suspension, specifically the fork. What did they do? Nothing. They have stayed with the now less common coil spring fork while other manufacturers have been left to sort out and evidently suffer with the newer air fork. And no one has yet to put an air fork on an off-road bike so the fit and timing is just fine for the YZ. The components are the same as the YZ motocrosser except in the setting. Yamaha has less low-speed damping internally with more high-speed damping to be more compliant on the bumps while still provide the stiffness and hold-up that a race bike needs.

And just like on all the previous YZ X bikes they have nailed it. The bike is not overly stiff for off-road nor is it too soft for going around a motocross track, There is a stiff plushness that lets the rider feel the ground but not get beat up. Compared to more trail bikes it is stiff and compared to motocross bikes it is supple.

Our testers ranged in weight from 160 pounds to over 200 and we did not really get one complaint about the action of the suspension. And of all the bikes we have been riding lately this one was played with less in clickers by a large margin. About the only thing that was noticeable is that if the rider height isn’t correct the stability can really suffer. We ran 103mm most of the time and once you get close to 100mm or less the headshake starts to creep in. For slower riding you can take about 4 clicks out of the low speed compression front and rear and it really deadens the feel of the suspension especially on rocky loose conditions. Same thing for the track in the opposite direction and you can have the YZ450FX holding itself up on jump faces and roller sections for most skill levels. Other than that small use-specific tuning we felt the action of the suspension was spot on.

The place where a suspension setting like this is really challenged is in sharp hits like roots or rocks where if it is too stiff the bike can deflect. The YZ somehow really lets its fork and shock move when it needs to but it also does not bottom as easily as we thought it would. We feel the weight actually helps the bike here keeping it planted and helping the suspension break into the stroke easier. The overall action feels like it is very progressive and balanced and maybe that little extra shock length helps with keeping the wheel moving when it needs to and not bottoming either. There is never the sensation the bike is wallowing and because of the excellent throttle control--this plays into the way the bike works.

We have not had any leaking on this bike’s fork seals yet but have noticed on other YZs that the seal life is shorter than expected, especially in muddy conditions. The conventional spring front end has been a strong point for all the YZ bikes and it still is. Yamaha has a lot of experience with both this and a familiar shock and they know how to set them up for the intended purpose, right in the middle of the setting range so riders can tune even farther.

Chassis - Handling

• A very surprisingly light feel for a heavy on the scale bike.
• Nimble thanks to quick steering and a very responsive motor.
• Stable too. Thanks to the motor again.

If we were surprised by the power and very impressed with the suspension, the handling was unbelievable. We will be the first to tell you that the YZ450F motocrosser has started to feel heavier over the years and we expected the YZX450FX to be a bit of a tank. On the scale at 264 pounds with a full tank of gas (253 empty) the weight isn’t very promising either. But it does not take but a few minutes riding the bike around for a rider to question the scale and wonder where Yamaha hid all those pounds. The 22mm clamp is a large part of this feeling but there is more to it than that. Especially in a front-to-back direction, weight on the front wheel or on the rear wheel the bike feels very agile and flickable (plus that great throttle response aids here). Even side-to-side the bike does not feel like a 450. We are speculating that this light feeling all has something to do with the thinner engine mounts and softer suspension when compared to the YZ and then the rearward slanted engine when compared to other bikes. In the air you can feel the weight a little bit but when pounding through whoops or dodging trees or rocks the YZ450FX is very surprising.  

The weight in the handlebar is just enough to inspire stability but not enough to feel heavy at all.

On the motocross track the FX surprised with its incredible turning in any condition and the ease at which it goes into the turns. It stays down through the middle of the turns better than other versions of this chassis/engine package where the have been issues but it still is a bit of a fight here compared to some other bikes. On the way out the 450 steers on the rear wheel like a champ and will slide and track depending on the throttle. Off-road where there is less consistency in turns the agility of the bike is apparent and helpful the tighter the turning gets. The combination of the suspension sticking the wheels to the ground and the throttle allowing quick bursts to help control everything makes the Yamaha a very potent 450 in the woods.

The brakes are very good with a 270mm front rotor helping the cause and the feel is on par with most systems. Dunlop AT81 tires are a good choice for durability and work better on the YZFX than most other bikes, especially the front. The layout is pretty roomy and all of the controls are just where they need to be. The handlebar clamp (runner mounted which minimises vibration) is four position so you can even stretch out the rider cockpit a little bit more if needed. We are glad Yamaha decided to include the skid plate for protection and after all the mounts sitting there in the wind like on the YZ250FX are ugly. And trust us our skid plate did work and passed the test. Working on the bike is simple. The high-mounted air filter is easy to get to. Oil changes are simple but you must remove the skid plate. Gassing the bike is a bit more trying, especially if you are doing it in a race. And the 2.0-gallon capacity is a touchy point for some. It will easily do a 45-minute GP but going past an hour is testy if the conditions are fast. We squeaked out 60-miles on a tank and were scared for the last 20-miles since you see the fuel level in the tank and it looks empty for at least the last ⅓ tank. One of the complaints the motocross bike suffers from but we heard less of it was that the bike felt wide. We know it isn’t wide where you actually touch it but it is wide up top of where the conventional tank and the radiator shrouds are due to the air intake there. We think since off-road riders are a little more use to a larger tank that often intrudes in this area, it wasn’t as much of an issue.

There is a big wide-open space under the seat that holds a lot of electric components out in the open and it seems vulnerable. But in use this area stayed surprisingly clean, even in muddy and sloppy conditions.

Conclusion

• Yes, the YZ450FX is a great bike.

Being skeptical we were not expecting that much from the YZ450FX. We know how the YZ motocross bike currently feels and how difficult it is to get it to work for off-road, so even seeing the spec sheet on the FX we were not totally impressed. But one ride on the bike had us very surprised. It feels lighter than it should, the power is impressive but not overwhelming and we feel Yamaha nailed it for multi-purpose stock suspension. We’ve been big fans of the YZ250FX and YZ250X thinking that there was no way that they could transform the 450 in the same ways. After all the bigger and more powerful bikes are typically more difficult to tune into a managable platform. But this may be the best Yamaha X bike yet. At $8990.00 Yamaha is also making a statement with the price being close to $1000 less than the bike’s direct competition, the KTM 450XC-F.

The YZFX is spoecifically built as a closed course competition bike and it is that. We see the majority of closed course off-road races as GPs, GNCC/Hare Scrambles and now even more popular the sprint enduro. For this and if you are looking at a 450cc bike the YZ is excellent. It can stretch into going trail riding without punishing the rider. It is a great motocross bike especially for the novice and intermediate-level real world rider.

There is no question that KTM owns this market segment and Yamaha is getting back into it, after all, they were strong here quite a while back. The four-stroke WRs of the past decade were trail bikes and not racers, so the FX is really a new concept that follows Yamaha’s definition of what the WR was back when it was a two-stroke 250cc bike.

So the real question is how good it compared to other bikes? While testing we’ve been comparing it to a lot of the other bikes in the class and will have those comparisons published shortly. But for now you don’t have to read between any lines here. The YZ450FX is a great bike with a lot of class leading characteristics that everyone will be shooting for.

If you have any questions that we didn't answer in the test, be sure to comment in the discussion below.