MXA RACE TEST: THE REAL TEST OF THE 2023 YAMAHA YZ450F

THE GEAR: Jersey: O’Neal Hardwear, Pants: O’Neal Hardwear, Helmet: Arai VX-Pro4, Goggles: Blur B-60, Boots: Sidi Atojo.

Q: FIRST AND FOREMOST, IS THE 2023 YZ450F BETTER THAN THE 2022 YZ450F?

A: Yes. Let’s be honest, even if the 2023 YZ450F’s performance were identical to that of the 2022 YZ450F, the 2023 YZ450F gets a lot more brownie points—not for kicking out the technological jams, but for finally paying attention to the obvious flaws that stuck out like sore thumbs since the first slant-back-engine YZ450F was introduced in 2010. Yamaha’s willingness to address the human element is what sets the 2023 YZ450F apart from its 12 predecessors.

Q: WHAT ARE THE MAJOR CHANGES THAT YAMAHA MADE TO THE 2023 YZ450F?

A: Let’s not reiterate the complete list for the hundredth time. This is not a machine that has been released into a vacuum; there has been more pre-release drama and a longer wait for the 2023 Yamaha YZ450F than any other bike in 2023. If you don’t know what Yamaha changed for 2023, then you aren’t getting very good internet reception in your basement lair. Here is the abbreviated edition:

(1) What didn’t they change? The wheels, forks, handlebars and brakes. 

(2) What did they change? Everything else.

Q: IS THE 2023 YZ450F FASTER THAN THE 2022 YZ450F?

A: Yes, but not in terms of sheer horsepower. More horsepower would have been the easy thing to achieve. Every brand, save for Suzuki, has built 60-plus horsepower engines as of late without making their powerbands one iota
better. Instead, these bikes became harder to manage, hang on to and maneuver.

The best accolade that the MXA wrecking crew could bestow on the 2023 YZ450F was that its power delivery was extremely linear, which maximized connectivity between the throttle and the rear wheel. That may not sound like a rousing review, but you have to feel it in motion to really appreciate it.

Thus, the new fuel-injected, downdraft, four-valve 2023 YZ450F engine is significantly better than its 2022 brother. Note that we didn’t say “more powerful,” because, in a statistical sense, it is not. Instead, it is significantly better in that, along with the total remake of the whole package, Yamaha’s engineers embraced the new style of power that has swept the 60-horsepower engines of a few years ago out with the tide. 

Q: WHAT IS THIS “NEW STYLE OF POWER” THAT IS SUDDENLY IN VOGUE IN 2023?

A: Virtually every 450cc motocross bike made in 2023 has knocked off a  horses  or two in pursuit of a kinder, gentler style of power. For example, the bikes that cracked the vaulted 60-horse mark in the last couple years are now below that halo horsepower mark on purpose . The only two bikes hovering just a hair below sixty horses are the 59.94-horsepower KTM 450SXF and the 59.30-horsepower Husqvarna FC450. The 2023 CRF450 went from the big six-oh to 56.31 horsepower and the lower power output calmed down the often-twitchy CRF450 chassis considerably.

As for the 2023 Yamaha YZ450F is now at 58.95, which is very close to what the 2022 YZ450F produced. It should be noted that Suzuki, GasGas and Kawasaki (save for the KX450SR Special Racer) never got anywhere near 60 ponies. The 2023 Suzuki RM-Z450 doesn’t crack 55 horses. The GasGas sits at an airbox-moderated 57.07 horsepower, and the 2023 Kawasaki KX450 hovers at 56.37 horsepower.

It took the factory engineers a long time to realize that pursuing the most horsepower was not a positive if it upset not only the rider at the controls, but also the chassis the rider sits on. 

Q: HOW WOULD WE DESCRIBE THE 2023 YZ450F’S POWERBAND?

A: At the first twist of the throttle, the 2023 YZ450F is ultra-responsive. It isn’t herky-jerky down low like last year’s YZ450F engine; However, it is overly sensitive to the slightest rotation of the throttle tube. At this singular point on the power curve, the 2023 YZ450F works against the rider. In the first 1/8th of an inch of throttle input, the YZ450F will pop out of ruts, snap the chassis slightly askew, and wheelie. And we don’t mean a graceful showboat wheelie; instead, it comes as a surprise. One second the bike feels balanced and hooked up, and a second later the front wheel is off the ground and the rider is mono wheeling in whatever his last direction was.

Remember way back in the third paragraph where we said the 2023 YZ450F “maximized connectivity between the throttle and the rear wheel.” We meant it as a compliment, but at the first twist of the throttle it is a big negative. Need proof? At 4300 rpm, the 2023 Yamaha YZ450F makes 12.33 horsepower. Shockingly, just 100 rpm later, at 4400 rpm, the horsepower has jumped to 20.31 horsepower. That is an 8 horsepower gain in 100 rpm—and it comes as a shock. If that rate of climb were a constant across 1000 rpm, the YZ450F would be making over 80 horsepower by the time it reached to 5400 rpm. Luckily, the YZ450F settles in to gain only one horse per 100 rpm for the next 2500 rpm.

After that initial jolt, the throttle-to-rear-wheel connectivity is amazing. The engine’s power curve is surprisingly linear. There are no dips, jolts or valleys to the delivery. It puts every ounce of internal combustion energy into the rear wheel. It makes the words “hooked up” take on real meaning. Yes, it is still wheelie prone every time you roll the throttle rearward, but it’s no longer a violent surprise.

Q: HOW DOES THE 2023 YZ450F RUN ON THE DYNO? 

A: Maximum horsepower on our 2023 YZ450F was 58.95 ponies. Maximum torque was 35.37 pound-feet. For comparison purposes, our 2022 YZ450F reached 59.29 horsepower and produced 36.07 pound-feet of torque. The dyno numbers may be very close, but the cigar goes to the 2023 YZ450F because of its seamless power delivery.

The 2023 rev limiter has been moved up 500 rpm, which allows for over-rev to 11,700 rpm. The only fly in the additional over-rev is that the YZ450F does not reach its peak horsepower until 9800 rpm. That is high in the range, given that the competition engines gets to their peak much earlier and all of the YZ450F’s competitors, save for the Suzuki RM-Z450, produce more torque—anywhere from one pound-foot more to the CRF450’s amazing two pound-feet more.

Q: HOW DOES THE 2022 YAMAHA YZ450F HANDLE?

A: After years of trying Band-Aid fixes on the earlier generations of YZ450F frames, Yamaha finally went all out on the new chassis they have needed for the last 12 years. Forget everything you ever knew about how your old YZ450F handles, the 2023 YZ450F is a new dawn. In the past, Yamaha engineers never fully embraced the turn-at-all-cost philosophies that guided the Suzuki RM-Z450 and Honda CRF450. For 2023, Yamaha has tried to mate aggressive turn-in with acceptable high-speed stability. That is almost an impossible balance to achieve, because you have to give to get.

Thus, for 2023, the Yamaha YZ450F turns in with the best of the super-accurate breed; however, there are conditions where there is more than a little over-steer at the front wheel and, conversely, a lot more head-shake at speed. Yeah, yeah, yeah, we know, “Yamaha’s don’t head-shake.” But they do now. This is a nervous chassis, always hunting and pecking for optimum traction.

With a careful selection of race sag and fork height settings, you can fight each malady as it pops up. This is the quickest and sharpest turning YZ450F ever, and, predictably, it is the least stable at speed.

Q: DID YAMAHA ADDRESS THE BIG, BULKY, WIDE, TALL, HEAVY AND LOUD COMPLAINTS?

A: Over its lifespan, the YZ450F has had the worst ergonomics of all the 450cc motocross bikes. Yamaha loyalists adapted to it, but from a pure performance point of view, it was a disaster to riders used to other brands. MXA was Yamaha’s biggest critic. We said that the bike was way too heavy (only 3 pounds less than the antiquated Suzuki RM-Z450), too wide (because of where and how much the radiator wings flared out), too tall (unfortunately, it got taller for 2023), too bulky (especially in its midsection) and too loud (with most of the noise pollution coming from the gas-tank-mounted air intake). Here is where the updated 2023 YZ450F falls in these five categories.

(1) Weight. The 2023 YZ450F weighed 233 pounds. That puts it right in the same weight class as the Honda and Kawasaki and only a few pounds heavier than the KTM and Husky. The GasGas is by far the lightest of the 2023 450 at 223 pounds. 

(2) Width. The airbox no longer breathes through the radiator shrouds, which allowed Yamaha to move the shrouds down closer to the radiators and inward 50mm. This, in addition to a 6mm-narrower fuel tank, eliminates the bulge of last year’s radiator wings. 

(3) Ergos. The new seat is much flatter for easier fore/aft movement, and it is 5mm taller. This raises the seat height excessively for riders under 5-foot-9, but does eliminate the previous feeling of sitting in a hole.

(4) Noise. Since the YZ450F doesn’t draw air into the downdraft throttle body via the radiator wings, the sucking sound has been reduced, as Yamaha now uses “undefined air” that leaks in and around the airbox.

(5) Bulky. The all-new 2023 plastic fits tighter to the frame to form a smoother interface. The slimmer and flatter seat makes the chassis 6mm narrower at the rider’s knees when standing. 

(6) Tall. The rider triangle is improved for taller riders by moving the footpegs 5mm down and 5mm back (and when combined with the 5mm-taller seat, the footpeg-to-seat-height measurement is increased by 10mm).

HOW DID THE NEW BELLEVILLE WASHER CLUTCH WORK? 

A: Yamaha’s new 2023 clutch is a direct copy of KTM’s Damped Diaphragm clutch, right down to the steel clutch basket with the primary gear CNC-machined into the back of the clutch basket (eliminating the old-school method of riveting a separate primary gear on the aluminum basket). Gone are the six separate coil springs, as they are replaced by a Belleville washer. KTM has used hydraulic clutches since 1998 and switched to Belleville washer-equipped units in 2012, but Yamaha still resists going hydraulic, instead relying on cable actuation. Yamaha does offer a bolt-on hydraulic clutch kit through its GYTR product line. Contrary to what you may believe, the YZ450F’s new steel clutch is 1.6 pounds lighter than the previous aluminum clutch.

However, MXA’s most serious clutch users, felt that Yamaha’s spring-rate choice for their Belleville washer was not sufficient for the load placed on it, and they felt the clutch go soft early on in motos and had to spin the clutch adjuster to keep up with the fade. Hinson will most likely produce a stiffer Belleville washer for the Yamaha YZ450F that will cure the clutch fade.

 

Q: WHAT DID WE HATE? 

A: The hate list:

The domed air filter has 56% more surface area.

(1) Airbox. The airbox has a higher capacity cover and sits 15mm lower on the frame. Plus, the previous flat-piece-of-toast air filter has been replaced by a domed air filter that has 56 percent more surface area. All of this is very good ,but is ruined by the fact that we had dirt migrate past the thin channel that the filter cage sits in—especially at the very front of the filter (be sure to grease it heavily), not to mention that the backfire screen is now integral to the air filter cage, which means that when you remove the air filter, nothing stops dirt from falling directly into the throttle body.

(2) Foot peg brackets. Every test rider complained about accidentally standing on the all-new aluminum footpeg bracket on the shifter side. It is very large. 

(3) Map switch/kill button. Be careful when using the small kill button, which is located above the larger map button. It is easy to change maps accidentally while killing the engine.

(4) Gearing. We geared the YZ450F up by going from the stock 49-tooth sprocket to a 48. This made second gear taller, which enabled it to be used as a replacement for both second and third gears, which took the burden off third to be the prime drive gear. Plus, it mellowed out the low-end power a touch to make the delivery more controllable.

(5) Crossbar pad. The best thing about the YZ450F crossbar pad is that it is larger than the diminutive GasGas bar pad, but both are one-fourth the size of a regular bar pad.

(6) Right side panel. Some test riders, depending on the brand of boots they wore, had the top of their boot snag on the right-side body panel.

(7) Seat. Although the new seat helps flatten out the riding position, its abbreviated pyramid shape means that it is an uncomfortable 5 inches wide where you sit and it makes the 2023 Yamaha YZ450F even taller than last year’s model.

(8) First-year model. The 2023 Yamaha YZ450F is the epitome of a first-year model, and, according to the unwritten manual of common motocross wisdom, you should never buy a first-year model. 

Q: WHAT DID WE LIKE?

A: The like list: 

(1) Oil tank. Yamaha returned to its old-style dry-sump lubrication system, and the oil tank is hidden in the front portion of the ignition cover. Clean and simple.

(2) Fork guards. The 2023 fork guards wrap around the fork legs, similar to both Honda and KTM fork guards. This cuts down on rock dings that cause fork seal leaks.

(3) EFI Power Tuner. Yamaha’s smart phone app GYTR Power Tuner is a self-contained WiFi device that allows engine settings to be changed via a slide bar. It also handles Launch Control, Traction Control, lap timing, maintenance records and engine runtime.

(4) Clutch cover. Yamaha cast an unpainted, dimpled clutch cover to keep the rider’s boot from scratching the paint off the cover.

(5) Maps. Most test riders wanted to stick with the stock map (map button not lit), but the bike was almost too fast, obviously too abrupt down low and  had to be revved higher than we felt comfortable on. At first we tried Yamaha’s optional “Smooth Linear” map (map button lit up) in hopes of taking the bark out of the low-end. It didn’t stop the YZ450F from wheelying  and eventually we built a much richer map between 2000 and 5000 rpm to help calm down the YZ450F’s rambunctious.  It seemed strange to be trying to slow down  its roll, but we wanted more manageable power and the GYTR Power Tuner offers that as a option 

Q: WHAT DO WE REALLY THINK?

A: The 2023 Yamaha YZ450F is one giant leap forward for Yamaha racers. It is a marvel of innovation, engineering, frame geometry and power management. But, much more than the Gyro Gearloose parts and pieces went into making the 2023 YZ450F what it is. There was an equal amount of “human factor” engineering to make sure that the end user’s concerns, complaints and issues were addressed, something that wasn’t considered when designing the previous generations of Yamaha YZ450s.

 

MXA’S 2023 YAMAHA YZ450F SETUP SPECS 

This is how we set up our 2023 Yamaha YZ450F for racing. We offer it as a guide to help you get your own bike dialed in.

KAYABA SSS COIL-SPRING FORK SETTINGS
Dating back to 2006, Yamaha has had the best forks on the track and has retained that crown for 2023. There have been modest updates every couple of years to keep abreast of the times as tracks have gotten rougher, jumps bigger and riders faster. But, Yamaha has never thrown the baby out with the bath water. Mid- to high-speed compression damping is perfect at keeping the front higher to lessen diving. Plus, Kayaba added KTM-style clickers to make compression adjustments by hand a snap. For hardcore racing, these are MXA’s recommended 2023 Yamaha YZ450F fork settings (stock settings are in parentheses).
Spring rate: 5.0 N/mm
Oil quantity: 270cc
Compression: 10 clicks out
Rebound: 13 clicks out
Fork-leg height: Flush
Notes: Most MXA test riders slide the forks up and down in the clamps to increase or decrease steering response—up for quicker steering and down to fight against the 2023 YZ450F’s tendency to head-shake at speed.  Most MXA test riders pushed the forks down into the clamps as far as they needed to stop the front end from shaking at speed.

KAYABA SHOCK SETTINGS
As always, no shock spring rate can satisfy every rider’s weight, riding style and track choices. This stock shock worked best for Pros and fast Intermediates, but most Novices and Vets felt compelled to go out on the low-speed compression clickers to undo what Yamaha had done.  For hardcore racing, these are MXA’s recommended 2023 YZ450F shock settings (stock settings are in parentheses).
Spring rate: 58 N/mm
Race sag: 105mm (100mm stock)
Hi-compression: 1-1/8 turns out (1 turn out stock)
Lo-compression: 12 click out (10 clicks out)
Rebound: 13 clicks out
Notes: Most MXA test riders preferred less high-speed compression. Yamaha puts a dimple in the rear fender to indicate where they want the race sag to be measured from.