Big Gains For The bLU cRU
Story and Photos by Trevor Hunter
The YZ250F has been a force to be reckoned with ever since the reversed engine design was implemented in 2014. In 2020, it was more apparent than ever in Pro Motocross seeing every Star Yamaha leading the pack into the first turn more often than not. At the consumer level, the bike has seen nothing but praise for the most part. So for 2021, Yamaha implemented the changes made to the 2020 YZ450F chassis wise, along with updating the motor package and some suspension settings.
The changes are abundant in 2020, but there seemed to be one common theme: aggressive. All of the motor changes are designed to increase power, especially at higher RPMs, and chassis and suspension settings are stiffer and more “precise.” SO what are those changes? Here are most of them in detail:
- Intake port shape is 3mm wider at the cylinder
- Exhaust camshaft opens 4 degrees later and closes 4 degrees sooner for bottom-mid power
- New air boot and throttle bottle joint allow more air and increased flow
- Water pump unit sees durability increases
- Cam chain tensioner has a new spring to stabilize chain at high RPM
- Clutch basket has added material and transmission gears are wider
- New muffler
- Smaller (240mm from 245mm) rear disc
- New front brake caliper, pads, and disc
- Less rigid front axle
- Frame thickness revised throughout, with different material motor mounts
- Updated suspension settings
- Thinner foot pegs
- Less rigid top triple clamp
Power: Yamaha has been known for its fast motors and they have done it again in 2021. The 2021 motor is even faster than the 2020 model. We had a 2020 model on hand to ride back-to-back, and the changes are apparent. The ‘21 has slightly better bottom end, but is more free revving and has stronger pulling power from mid-top. Overall, the power is more exciting over the previous year, though we also say it’s easier to ride if you get lazy. You can rely even more on the Yamaha’s torque and can roll corners and short shift without the bike falling on its face which was not even a problem to begin with! Also, the throttle feels as if it’s connected to the rear wheel. The instant you crack open the throttle, the rear wheel matches it. Whether we wacked it wide open, or used a smooth roll-on method, the bike responded instantaneously.
With the power tuning app on these bikes, it’s hard not to love them. The app allows you to adjust the motor in all different ways. The bike can be more friendly to different levels of riders and different forms of riders. While the stock map is good, both of our younger and faster testers preferred the “Exciting Map” from Yamaha. It boosted power across the range, but was most noticeable down low. The extra power had a harder hit, but allowed us to ride a gear high if needed and smoothen out our riding style.
Suspension: Yamaha suspension has always been some of the best and the ‘21 YZ250F is no different. The KYB components offer a lot of comfort, but still enough performance and hold up to handle hard, aggressive riding. The stock setting was a little soft up front, causing the bike to not want to settle and dive in the braking bumps. After stiffening the compression two clicks and speeding up the rebound two clicks, the bike worked much better for our hard charging riders. The front end stayed up in the stroke more and resisted diving and bottoming in the bigger and faster bumps. Still, even when the forks would bottom, it was a very controlled and smooth bottoming. Out back, the shock worked very well soaking up small acceleration chop while absorbing big jump landings and braking bumps.
Handling: The feeling of the ‘21 YZ250F has changed to a more rigid feel than the 2020 model, which isn’t a bad thing at all. The bike acts more precise, nimble, and overall feels lighter with the balance staying the same. This is exactly what we expected (and hoped for) after realizing these changes on the 450F, though not as many of us are fans of the new 450 feeling. With the 250, riders tend to be more aggressive and the added precision and a slightly stiffer feeling is typically a good thing. Coming into corners, you could move around going in and drive out with an increased ease. Mid corner the bike stayed planted in ruts and would respond well to rider input and direction changes.
Geometry: The 2021 now comes with the bar mounts on the front (or forward) setting of the top triple clamp. Our riders were a little skeptical about it, but our taller riders ended up enjoying it a lot. The bars being further forward gave the YZ a more stable feeling. The negative to putting them forward did not allow the bike to turn as well in sharp turns which is the opposite of normal effects typical to a change like this. To combat this, we ran slightly less sag (102-104mm) and turning came back around. Yamaha have had the bar mount option for a while, but this is the first year it comes standard in the front setting. Our smaller riders would like to go to the back mount for a comparison, but it was still more than rideable for a 5’7 frame. The rest of the ergos feel fine, though a tall seat, like on the 450, is welcomed by all of our riders. We like the tall seat for a few reasons. The stock seat was a little soft, so the tall seat gives more cushion allowing to make those rough ruts and chop sitting down a lot more smoother. Also, it makes the rider cockpit feel more comfortable as you sit on the bike and not in it like you do with the stock seat. On our 2020 YZ250FX, we went to a lower set of handlebars and we got the same feel as if running a tall seat with the taller stock bars.
Overall, the 2021 Yamaha YZ250F is a very good bike. It’s hard to believe, but the bLU cRU again made improvements for the majority with this bike, even in power so it isn’t going to get any easier for the other 250Fs. The motor is noticeably stronger and has a broader power spread than previous. You can rely on the excellent torque per usual, but you can rev it out even more like a traditional 250F with improved results. Suspension wise, it’s tough to beat Yamaha and the new settings have better hold up in the big stuff without sacrificing too much comfort on the small bumps. The chassis updates make the bike feel lighter, more nimble, and much more precise than in years past. We’re a fan of the changes made for 2021, it’s unikley the competition feels the same way.
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