MXA RACE TEST: 2017 YAMAHA YZ450F: A LOT GOING ON & NOT ALL GOOD

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Q: FIRST AND FOREMOST, IS THE 2017 YZ450F BETTER THAN THE 2016 YZ450F?

A: Incrementally better, but you don’t need to throw away your 2016 YZ450F—it’s still virtually the same.

Q: WHAT CHANGES DID YOU THINK YAMAHA WAS GOING TO MAKE TO THE 2017 YZ450F?

A: Forget all the talk of an electric-start 2017 YZ450F with a forward-slanted engine, air forks and hydraulic clutch. Ain’t gonna happen. There are several reasons why the rumormongers were wrong from the get-go: (1) Cycles. The 2017 Yamaha YZ450F was in the fourth year of its development. The Japanese have become so regimented in their production schedules that we predicted with some assurance that new models come out at four-year intervals. Thus, if there is going to be a totally new YZ450F, it won’t hit until the 2018 model year. (2) Weight. The Japanese manufacturers cannot afford to just throw an electric starter onto their existing models. Why not? The 2017 Yamaha YZ450F weighs 238 pounds (without fuel). If you added an electric starter motor, necessary gears, electronics, wiring harness and battery, you’d be lucky to get it done in less than 5 pounds. That would make the YZ450F weigh 243 pounds—21 pounds heavier than a 2017 KTM 450SXF. Can you say “dead weight”? (3) Mass. Yamaha is committed to its rear-slanted engine design. It offers excellent down-draft geometry for the throttle body, improved centralization of mass and addresses the issue of rotating engine mass. All good things—and all things that are proprietary to Yamaha. We don’t see Yamaha making an about-face any time soon. (4) Consumers. There would be a riot at your friendly local Yamaha dealership if YZs arrived on the showroom floor with touchy, complicated, troublesome Kayaba PSF-2 or Showa TAC forks on them. Yamahas only work as well as they do because of their coil-spring forks—and the PS-2 and SSF-Tac using brands suck wind because of their air forks.The 2017 Yamaha YZ450F is the 2016 YZ450F with recessed bolts on the airbox cover. That may sound like coasting by the Yamaha R&D department, but they made a lot of changes in 2016.

The 2017 Yamaha YZ450F is the 2016 YZ450F with recessed bolts on the airbox cover. That may sound like coasting by the Yamaha R&D department, but they made a lot of changes in 2016.

Q: WHAT CHANGES DID YAMAHA MAKE TO THE 2017 YZ450F?

A: Before you get upset that Yamaha didn’t reinvent the wheel for the 2017 model year, you need to remember that one year ago the YZ450F got a major overhaul. These are the 2016 upgrades:

(1) An exhaust cam with 0.3mm more lift, 8 degrees less duration and less overlap. The intake cam got 0.1mm less lift.
(2) The valve springs were made stiffer and designed to eliminate coil bind at high rpm.
(3) The gear stopper lever got a plain roller that was supported on both sides and retained by a 20-percent stiffer spring.
(4) The 2016 Yamaha YZ450F got a new dog shape on the gears, and the gap for neutral was reduced to lessen the chance of missed shifts.
(5) Yamaha added a launch control system that ramps back to maximum power approximately 60 feet off the line.
(6) The fork offset was changed from 22mm to 25mm, which was a return to the previous offset.
(7) The rear shock spring was softened from 58 N/m to 56 N/m, while the fork springs were stiffened.
(8) The frame was stiffened torsionally by widening the swingarm pivot forgings by 12mm.
(9) To fight engine shake and chassis flex at the front of the frame, the head stays were made bigger, thicker and stronger.
(10) The 2016 YZ450F footpegs were lowered 5mm (and can be installed on older-model YZ450Fs).
(11) The 2016 Yamaha YZ450F got a 270mm front rotor to boost its braking power.

17yzairbox

Q: SO, WHAT DID THEY CHANGE FOR 2017?

A: Five things were changed:  (1) recessed holes for the gas-tank cover’s Dzus fastener to hide in, (2) an improved seal on the countershaft sprocket, (3) an updated oil strainer, (4) improved metal in the rear rotor (to lessen its tendency to warp), and (5) a switch from MX52 to MX3S tires.

Q: IS ANYTHING ELSE NEW ON THE 2017 YAMAHA YZ450F?

A: No, unless you count the radiator wing graphics.

Q: HOW DOES IT RUN ON THE DYNO?

A: Given that the 2017 YZ450F engine package is identical to the 2016 mechanicals, it makes the exact same horsepower. It peaks at 56.85 horsepower at 9800 rpm. That’s solid, but really unchanged mathematically from the 2015 and 2016 engines.Yamaha has everything it needs to be a winner. It’s fast, well suspended and bulletproof. So why isn’t it a winner? Because it weighs 16 pounds more than a 2017 KTM 450SXF.

Yamaha has everything it needs to be a winner, just not in the correct quantities. It’s fast, well suspended and bulletproof. So why isn’t it a winner? Because it weighs 16 pounds more than a 2017 KTM 450SXF, has cranky handling and is  jumbo-sized.

Q: WHAT DO WE THINK OF THE WAY IT RUNS ON THE TRACK?

A: If forced to describe the way the 2017 YZ450F runs in five words or less, we’d say, “Like a scalded cat!” You don’t find a lot of mid-to-top powerbands in the 450 class. Well, not actually, the YZ450F and the 2017 CRF450. Normally, the engine designers are trying to trade burst and blast for manageability. Not Yamaha—although Yamaha did give lip service to filling in the low-to-mid transition with last year’s cam change and richer mapping. The Yamaha YZ450F engine (2015–2017) is akin to a runaway Audi 500 with granny behind the wheel. It does its best work beyond 9000 rpm—and 9000 rpm is so far up there in the world of 450 four-strokes that we consider the big Yammer to be best suited to Pro-level racers. It is easy to ride if you ride it slow, but most of the time it’s a rocket to the moon.

yz4502017jump

Q: WHAT DID WE DO TO IMPROVE THE YZ450F’S POWERBAND?

A: Take this to heart—we weren’t looking for more horsepower. The YZ450F has plenty of that. Instead, we were trying to get the power better positioned. We tried different maps on the 2017 YZ450F and had some luck with GYTR Power Tuner maps that were slightly richer on fuel at high rpm and seriously advanced on the ignition timing at every point on the curve. If you want a mellower powerband, go richer in every box on the fuel map and retard the ignition by at least 2 degrees in every box on the ignition curve. Given our druthers, we would combine our favorite map with a Steahly flywheel weight. Counter-intuitively, we added one tooth to the rear sprocket (from 48 teeth to 49 teeth). This gave us more thrust from gear to gear, but most of all it helped us get to third gear sooner where the new mapping and heavier flywheel weight could churn out of corners.

What didn’t we like about the YZ450F powerband? If you got aggressive coming out of corners, the abrupt hit would lift the front end. No big deal if it lifts in the direction you want to go, but more often than not it lifted too soon and pushed the bike outward.

What did we like about the YZ450F powerband? This is a holeshot machine. Its pronounced low-to-mid transition and excellent launch control system allow the YZ450F to come off the line straight as an arrow. Then, the afterburner kicks in from mid to top. If you are brave enough to leave it on, you will be first to the corner.

YZlinkage

Q: HOW DOES THE 2017 YZ450F HANDLE?

A: Most MXA test riders don’t like it. They don’t hate it, but look the other way when test bike assignments are handled out on race days. Sad but true. It’s vague at tip-in, tends to push on flat corners and has a hitch in its giddy-up at mid corner. This is more of a problem for MXA test riders than normal people because MXA test riders switch from bike to bike every race and often between motos. If our testers only raced Yamaha YZ450Fs, they would adapt their riding styles to the powerband and the chassis setup peccadilloes.Over time they would seem natural. But, when you get off of a Suzuki RM-Z450 onto a Yamaha YZ450F, you can’t help but notice that the Yamaha is wanting in some cornering areas. When you get off a KTM 450SXF, you can’t help but notice how broad the power is, light the chassis feels and how awesome the brakes are compared to the YZ450F.

You might be surprised to learn that most of our engine changes (mapping, flywheel weight and gearing) were made in the name of handling more than horses. But, we did make a lot of chassis changes. Here’s the list:

(1) Fork height. We slid the forks up in the clamps to steepen the head angle and to put more weight on the front wheel. This lessens the looseness at the entrance to turns, but it requires trial and error to avoid oversteer.
(2) Sag. We lowered the rear sag from 100mm to 103mm in conjunction with sliding the forks up. This got rid of the YZ450F’s inherent stinkbug seat height.
(3) Linkage. A longer shock linkage helped even more with chassis balance and worked well with the slightly softer shock spring that the engineers added in 2016.
(4) Clicks. Most of our rear shock adjustments were made with the high-speed compression adjuster. We tended to turn it out to help the rear settle more under a load.

We aren’t YZ450F defenders. We know, better than most, that the YZ450F can be awkward-feeling on the entrance to flat or sweeping turns. We have been critical of Yamaha’s front-end response for as long as we can remember. Superb handling has never been a Yamaha strong point—suspension, yes; cornering, no. A contributing factor to the YZ450F’s ungainly feel is its weird ergonomics. In stock trim it feels too tall in the rear. It gives the impression that it’s overly wide at the radiators. It feels tippy and top-heavy. It isn’t flat enough for our tastes. And, creative centralization of mass can’t make up for it’s 238 pound weight (without gas in the tank).

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Q: IS WEIGHT A DEAL-BREAKER?

A: Of course it is. A few years ago a 450cc motocross bike could get away with being this heavy, but all that changed when KTM knocked 12-1/2 pounds off of the 450SXF in three short years. Sadly, for Yamaha, Honda, Kawasaki and Suzuki, losing enough weight to keep KTM in their sights requires a massive investment in new engine designs, downsized castings and a retreat from their Delta-box aluminum-frame fixation. Given the sales of most Japanese 450s, they aren’t ready to invest mega-cash it what it would take to get anywhere close to KTM and Husky. Worst of all, if you don’t lose enough weight once you’ve invested the cash, you have to live with it for four long years. The Yamaha isn’t the heaviest bike on the track for 2017—the Suzuki RM-Z450 is—but compared to the KTM, it’s a tub of lard.

And the extra weight is a burden on the engine, clutch, suspension and brakes. It’s even a burden on the brakes in your truck when you have it in the back. Every component has to work harder when the mass increases. The Yamaha has way too much mass. Now, you may think that the same holds true for the mass of a 210-pound rider over a 150-pound rider. But rider weight is not a true factor, because the rider weighs what he weighs regardless of which brand of bike he rides — thus a lighter bike is a still a benefit.

The YZ450F powerband can be made more usable by new mapping and a 9-ounce flywheel weight.
The YZ450F powerband can be made more usable by new mapping and a 9-ounce flywheel weight.

Q: WHERE ARE THE AIR FORKS?

A: Hopefully, they are in a dumpster behind the Yamaha factory. Yamaha’s Kayaba SSS suspension uses old-fashioned coil springs. Guess what? Coil springs never go flat. Unlike air pressure, coil springs follow the ground for improved control. Coil springs have a linear rate change that works well with a hydraulic oil-damping system — air pressure ramps up violently. Coil springs don’t need to have the spring rate changed when the temperature fluctuates. No one ever comes in from a moto and says, “I think I need to change my springs before the second moto.” All of these complaints would be meaningless if the fancy air forks were better, equal or even close to as good as Yamaha’s Kayaba SSS suspension, but they aren’t. SSS is so much better than the new breed of air forks that it’s no contest. The only air fork that comes close to SSS performance is the WP AER fork on the KTM and Husky.

We feel a bit conflicted complaining about the porcine heft of the 2017 YZ450 while praising its 3-pound-heavier fork; however, there are a boatload of factory riders who have eschewed air and its weight savings to return to the brotherhood of the coils. And we don’t expect the Big Four Japanese manufacturers that are left in the air fork brigade to stick with them for long.

yz450frontbrake

Q: WHAT DID WE HATE?

A: The hate list:

(1) Exhaust pipe. Removing the YZ450F’s snake pipe is easy—right up until it is almost impossible. Do you own a 1/4-inch ratchet with a long extension and swivel-head 10mm socket? You should.

(2) Radiator wings. A tape measure will prove that the Yamaha radiator wings are not much wider than any other brand’s wings, but that isn’t what your brain tells you.

(3) Gearing. Experiment with a 49 for your local track.

(4) Noise. The sound coming out of the YZ450F’s muffler isn’t any louder than any other bike’s, but the cacophony from the front-mounted airbox takes some getting used to.

(5) Weight. Too heavy. This bike and the Suzuki are why electric bike stands were invented

(6) Yama-thumb. Bleeding has always been a part of Yamaha ownership.

Footpegs have come a long way in the last five years. Not only have they gotten wider and stronger, but 5mm lower.
Footpegs have come a long way in the last five years. Not only have they gotten YZ footpegs wider and stronger, but 5mm lower (and fit on 2015 and older models).

Q: WHAT DID WE LIKE?

A: The like list:

(1) Dzus fasteners.
We appreciate that Yamaha recessed the Dzus fasteners on the tank cover so that they would stop falling out or hooking on our pants, but a blind monkey could design a tank cover that locked in place with no Dzus fasteners. So, kudos on the recessed Dzus fasteners, but we still hate them.

(2) Reliability. We would guess that high on the list of reasons why racers buy YZ450Fs is because they are bulletproof. There are YZ450Fs out there with hundreds of hours on them with nary a valve adjustment to their credit. Nothing is as reliable as a Yamaha YZ450F.

(3) GYTR Power Tuner. The GYTR Power Tuner ($291.95) is the easiest-to-use programming tool in the sport. It’s like a Playstation for your fuel injection.

(4) SSS. The buzz of air forks is starting to wear thin on the consumer who craves not just performance but simplicity. Forks with multiple Schrader valves sticking out like the guns in a B-17 ball turret are an impediment to sales, not an incentive.

(5) Clutch. We run stiffer clutch springs, but the YZ450F clutch is better than most non-hydraulic clutches.

(6) Power. The 2017 Yamaha YZ450F doesn’t make the most horsepower in the 450 class, but it feels like it does.

Q: WHAT DO WE REALLY THINK?

A: The question is: Are you willing to live with an overweight, upright, oversized chassis to get awesome suspension, incredible mid-and-up power and money-saving reliability? It’s as simple as that. For the MXA wrecking crew, we think we can find better all-around performance without the compromises. We used to think the YZ450F was just quirky, but now we think that it saw its better days a few years ago.

MXA’S YAMAHA YZ450F SETUP SPECS

YZ4502017sidejumpThis is how we set up our 2017 Yamaha YZ450F for racing. We offer it as a guide to help you find your own sweet spot.

KAYABA SSS FORK SPECS
Companies that have latched on to air forks are gambling with your money. Yamaha’s SSS suspension is a sure thing. Maybe, eventually, air forks will be this good, but that’s not today’s reality. For hard-core racing these are MXA’s recommended 2017 Yamaha YZ450F fork settings (fork settings are in parentheses):

Spring rate: 0.50 N/m
Oil quantity: 315cc
Compression: 10 clicks out (8 clicks out)
Rebound: 8 clicks out (10 clicks out)
Fork-leg height: 4mm up
Notes: For 2017 Yamaha has refined what were already the best forks on the market. What’s best about them? They work for Beginners, Novices and AMA Pros. They don’t care if you’re thin or fat, tall or short. There’s a setting for everyone.

KAYABA SHOCK SETTINGS
For hardcore racing these are MXA’s recommended 2017 YZ450F shock settings (stock settings are in parentheses):

Spring rate: 56 N/m
Race sag: 103mm (100mm)
Hi-compression: 2 turns out (1-1/2 turns out)
Lo-compression: 12 clicks out
Rebound: 9 clicks out (14 clicks out)
Notes: We ran a longer 143.5mm Pro Circuit shock linkage—not solely for suspension purposes, but also to give us more adjustment room with the head angle and frame geometry. The longer link drops the rear of the bike almost 8mm and stiffens the initial part of the stroke. We compensate for this move by turning the high-speed compression out a half turn and the rebound in five clicks.

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