If you watched any of the 2020 Lucas Oil Pro motocross series, you might think that the Yamaha YZ250F is the all-time horsepower king of the 250 class. The bikes ridden by Dylan Ferrandis, Justin Cooper and the other Star Racing/Monster Energy team members were the fastest machines on the track, hands down. You gotta wonder, though, how much of that is Yamaha and how much is factory secret sauce? The Yamaha has a history of being torquey and easy to ride but not especially fast. We weren’t sure if that was going to change for 2021. The bike looks virtually identical to the 2020 version, but Yamaha was hinting about significant internal changes.
LOOKS THE SAME, TASTES DIFFERENT
Once you get past the fact that the top end of the Yamaha motor has the intake in front and the exhaust in back, it’s actually a little old-school. It still uses double overhead cams positioned directly over the valve buckets, whereas Honda, KTM, Husqvarna and Kawasaki all use finger-followers for additional leverage to open the valves. Engine tuners say that finger-followers are especially beneficial for peak power. Still, the Star bikes are so fast, we can’t say that the cam-over-bucket design is dead. The 2021 YZ250 has very few changes in the valve train aside from a redesigned exhaust cam. Most of the emphasis has been in improving airflow into the motor. The intake port has been reshaped, the Mikuni throttle body is larger, the air boot was reshaped and the airbox lid is vented. On the other side of the motor, the exhaust system was redesigned with a longer canister. The ECU has a new curve, and there have also been durability changes to the cam chain, cam-chain tensioner, gearbox, clutch basket and water pump.
- Excellent suspension
- Improved power delivery
- Wi-Fi EFI adjustability
- Excellent brakes
- Reliable clutch
- Unexceptional peak power
- Loud exhaust and intake
- Cramped riding position
- Awkward gas cap
- Engine type: Four-valve, electric-start DOHC four-stroke
- Displacement: 250cc
- Bore & stroke: 77.0mm x 53.6mm
- Fuel delivery :44mm Mikuni EFI
- Fuel tank capacity: 1.6 gal.
- Transmission: 5-speed
- Lighting coil: No
- Spark arrestor: No
- EPA legal: No
- Weight, no fuel: 227 lb.
- Wheelbase: 58.1”
- Ground clearance: 13.2”
- Seat height: 38.2”
- Front tire Bridgestone Battlecross X20F 80/100-21
- Rear tire Bridgestone Battlecross X20R 90/100-19
- Fork KYB inverted, adj rebound, comp, 12.2” travel
- Shock KYB, piggyback, adj. preload, comp, rebound, 12.5” travel
- Country of origin: Japan
- Price: $8299
The Yamaha’s chassis got some invisible changes in construction, which were introduced on the YZ450F in 2020. The engine top mounts were changed from aluminum to steel, while the front mounts were changed from steel to aluminum. The triple clamps are said to be less rigid, while the front axle is larger and presumably more rigid. All this is aimed at making the chassis more compliant in some planes and stiffer in others. Other changes include a beefed-up front brake, a smaller rear brake rotor and new suspension valving.
Even if the 2021 Yamaha YZ250F hasn’t changed that much, its role in the 250 motocross world has. That’s because the class has undergone rapid evolution in a very short time. For years, the KTM was the high-rev king, while Honda, Yamaha and Kawasaki took turns ruling the underworld of low-rpm torque. In 2018, Honda left the club and went all in for peak power. Yamaha followed half-heartedly in 2019; the new electric-start version traded away some low-end power for a little more on top, but not nearly to the extent that Honda had. Kawasaki was next. In 2020, the KX250’s valve train was redesigned, giving up what had been the best torque in the class for high-rpm scream. Yamaha was once again at the bottom of the class when it came to peak power.
Have things changed for 2021? First things first, Yamaha’s modest changes were fairly effective. The bike has more peak power than before, and it lost none of its low-rpm appeal. It still comes on at lower rpm than anything currently in the class—only the Suzuki comes close. In the middle, though, the Yamaha comes on much harder than the Suzuki. It even out-pulls the Honda and the new Kawasaki for a brief moment as the motor ramps up. When you really start screaming, the Yamaha hangs in there, but it’s clear that the motor is running out of steam. It starts to taper off just when the screamers of the class are going crazy.
For most riders in the real world, that’s not a bad formula. The lower midrange is where the dirty work of racing happens for almost everyone. This is real-world power, too, not just dyno power. To explain: On the dyno, the throttle is always wide open, even when measuring the low-rpm ranges. On the track, the throttle is rarely pinned to the stop. Even the best riders operate in the half-to-three-quarter range, and that’s where the Yamaha shines. If you want a little more top or bottom, some adjustability is possible through Yamaha’s Power Tuner app. This is a great feature—that’s clear from the way that other manufacturers are scrambling to develop their own versions. This allows you to adjust fuel mixture and spark advance through Wi-Fi connectivity to your phone. You can’t change a Yamaha into a KTM, but you can make a difference. We always look forward to the maps that the Yamaha testing department comes up with each year. We have tried to do better ourselves, but Steve Butler, Stevie Tokarski and Travis Preston are really good at what they do. Their rev map this year was a hands-down winner. For a screenshot of the map, go to
www.dirtbikemagazine.com and search “Riding the 2021 Yamaha YZ250F.” Technically, you should be able to download maps from Yamaha’s website, but this is hit-and-miss depending on your phone. The most reliable method is to input the values one by one. Be forewarned: there are 48 numbers to plug in. Clearly, some simplification is needed here.
YZ FAMILY VALUES
You can always count on some things to be constants in the motocross world. One is the fact that the YZ has excellent suspension. Yamaha messed with minor details again for 2021, but the basic formula still works. The fork is a coil-spring KYB SSS unit, and the rear suspension has changed very little over the years. Both work exceptionally well. As in the past, the spring and valving rates favor bigger/heavier riders but have a broad range of adjustability. The happy zone is a 170-pound intermediate, but even a 140-pound Novice can get away with the stock hardware. The clickers are that effective.
Yamahas also have a distinct flavor in the overall handling department. It’s a very stable package. You pick your line and gas it. That holds true in the turns as well as in the straights. Once you commit to a line in any given turn, the YZ follows its course like a bloodhound. Again, that hasn’t really changed in 15 years. Likewise, Yamaha’s ergos have become very distinctive. It’s a big-feeling bike overall, but tall riders still say they’re a little cramped. Many prefer the tall saddle from Yamaha’s accessory department. You can also move the bars forward or backward to suit your style.
Where does the new Yamaha sit in the world order? The YZ identity as the easiest, most user-friendly bike in the 250 world will go unchallenged in 2021. KTM, Husqvarna, Honda, Kawasaki and now GasGas will continue to appeal more to the revvers of the class who will sacrifice it all for every scrap of peak power. The irony is that even this YZ would have been considered a screamer by the standards of just four years ago. Even though it has changed dramatically over time, the motocross world has changed more.