Yamaha is no stranger to changing things up in the motocross game. In 2010, the company’s radical redesign of the YZ450F was met with mixed success, pushing the handling to new levels for some but frustrating some other high-profile racers. But even in the face of adversity, the core concept of a reversed cylinder head and rear-slanting cylinder has been retained. What’s more, there’s even more emphasis on mass centralization with the new 2014 Yamaha YZ450F.
After spending two days testing the 450 at Zaca Station Motocross Park in California—in which Ryan Dudek and I tried different tuning options and learned about the bike from Yamaha’s R&D; staff—we came up with the following points, which should give you a good overall feel for the new machine.
The new YZ450F is a complete package. There’s no standout feature because everything works so well together. The new seat (which covers the fuel cap) allows the rider to sit wherever, especially on the very front of the seat. Unlike a lot of MX seats, there is great cushion. The motor, the suspension, the handling, the ergonomics...they all combine to make the new YZ a bike you can ride without thinking about it much.
The motor is much improved. Yamaha claims nearly 55 hp, but the standout characteristic is the underlying feeling of torque that the older YZ did not have. The new YZ is smoother on the bottom, yet it’s reminiscent of a 250F in how quick it can rev. Outright power is impressive, and the excellent control via your wrist is just what a 450cc bike needs.
You can still use the GYTR tuner to alter the ignition and fuel delivery. But unlike the older bike, which really needed to be tweaked, the 2014 YZ feels impressive from the get-go. The keys for tuning: Adding fuel makes it feel like you are getting better traction and sort of slows the speed at which rpm builds. Adding ignition advance makes the bike more responsive. We built a map we liked that added fuel (+3) and took out ignition advance (-2) of the high rpm and big throttle openings.
The transmission shifts better and smoother, and it will accept wide-open-throttle/no-clutch upshifts. The clutch action is smooth and consistent, but the lever pull is a bit on the heavy side right as the lever starts to move in its arc. The dual-stage ignition programming has a smoother curve for first and second gear, and a stronger pulling curve for third through fifth. The gears feel evenly spaced. We tried adding a tooth to the rear sprocket to allow easier pulling of taller gears in the corners but it seemed to tighten up the ratios too much.
The motor’s oil capacity is reduced to one quart (0.95 liters), and the suggested change interval is down from 12.5 hours to 7.5. Yamaha’s research shows that most owners were changing the oil at closer to 4 hours of operation anyway.
The YZ still has a “follow-the-front-wheel” steering feel. It likes to be steered around turns, as opposed to slid around them. This feeling is a little strange because a lot of the bike’s mass is rearward compared to other bikes in the class. Additionally the rear of the bike is a little more reluctant to step out, or be flicked out to the side when in the air. But when it does, the bike loses its light feel and reminds you it is a 450.
This YZ turns like a motocross bike should, whether you’re accelerating, decelerating or using constant throttle. You don’t have to use the throttle to steer unless you want too. And when you get into turns, the steering seems to have a heavier feel. Some riders complained about the extra effort needed, while others felt like it added stability. Overall, you have a lot of control of the YZ in the turns, especially if you’re comfortable moving all over it like you can.
The suspension is improved. There is less fore/aft seesaw motion in acceleration or braking, or when hitting bumps in turns. By adding compression damping and playing with the high-speed compression on the shock, we could really alter and improve the bump feel and the bike’s attitude in the turns.
Even though the new YZ is shorter and more compact, it’s no less stable. And if it feels unstable to you, dropping the ride height can help a ton. Yamaha likes the sag to be set between 100 and 105mm, but we went all the way to 108 without losing any turning ability. I also improved the stability in high-speed chop. If you are uncomfortable with this aggressive cornering, just lower the ride height (or high-speed compression on the shock, it sort of does the same thing) until you’re happy. Then, as you get accustomed to it, raise the rear of the bike back up to the recommended setting. It works much better in that range.
The major chassis change, bringing the headset and front frame rail 10mm closer to the engine, shortens the wheelbase, and the additional tooth on the rear sprocket has moved the rear a bit closer to the front. The crank center, swingarm pivot and countershaft sprocket are all in the same position as they were in the old bike. The main effective change is the front wheel being 10mm closer to the crank.
The design team never considered abandoning the rear-facing exhaust or the rearward slant of the engine. And although they see an advantage in keeping the weight where it is, they say the real advantage is in the engine’s straight intake tract. Additionally the air filter, located on the front of the bike where a traditional gas tank would be, stays cleaner because it does not suck dirty air kicked up by the rear wheel.
During Yamaha’s testing, the engine mounts got a lot of attention. The larger upper one is made of steel. Its shape, and its material, are said to play a big role in the comfortable feel of the new YZ450F. This is an example of the high level of tuning that goes into chassis development these days. The thickness of the frame spars and the shapes and positions of the cross members are also very important.
To fit the muffler closer to the machine’s center of gravity, the lower right-side tube of the subframe had to be raised up to make room. The stock muffler is effective at keeping the sound reasonable in volume and pleasing to the ear.
The new Dunlop MX51 FA front tire is standard on the YZ. The Zaca Station track, and the turning prowess of the YZ, tested the performance of the tire, especially in the area where it’s claimed to be most improved—transitions from soft and wet dirt to hard pack and vice versa. We’ll need to get it on more familiar soils to confirm the level of improvement. But for sure, the new YZ needs a good front tire that the rider trusts.
Yamaha did a really good job of smoothing and simplifying a lot of the plastic on the YZ. There are fewer pieces and less hardware. Additionally, we had no issues with hooking boots or gear on any of the edges. Another bonus: Access to the air filter and tilting gas tank is simple. Fueling, by unplugging the front portion of the seat and unscrewing a cap, is not inconvenient at all. But we’re sure off-road racers (remember the YZ is designed as a motocross only machine) will take issue with this.
- The new YZ450F feels and acts very light, lighter than a 450 should, but it’s deceiving at times. When you get it to kick around or step out unexpectedly, this Yamaha will remind you that it’s a 450. Yamaha has done a great job of masking that, but completely hiding the true weight (Yamaha claims a wet weight of 245 lb.) is impossible.
For sure, the 2014 YZ 450F is improved. It’s easy to feel after a short time on the bike. It makes the old YZ feel a little bulky. Additionally, the previous YZ pitches forward and back and uses way more suspension stroke when riding. The motor, too, is much better. Although the list of improvements on the spec sheet is long, it’s the performance of the bike that matters most. Only some back-to-back tests with the other 2014 models will tell the full story, but if you liked this Yamaha in the past you’re going to lover this new one that much more.
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