3rd Place Of The 2019 450 MX Shootout: Yamaha YZ450F
The Yamaha YZ450F was all new last year and was well received for its excellent engine, plush suspension, and improved ergonomics. For 2019, Yamaha made some calculated changes to further refine its flagship motocrosser, including an updated electric starter system designed to reduce drag, a one-tooth-larger rear sprocket (going from 48-tooth to 49-tooth), and new, more rigid front and rear axle wheel collars. Engineers also threw stiffer compression damping on the fork and shock, added stiffer seat foam, and a retention tab to the right-side number plate. The bike keeps its powerful and user-friendly engine with lots of tuning capability from the the free Yamaha Power Tuner app. The result is a motocrosser with the plushest suspension of all the machines we tested as well as class-leading stability and predictability. With improved handling and ergonomics, this is the best YZ450F we’ve ridden to date.
The YZ450F engine was completely redesigned last year, and it remains the same for 2019 with the exception of a new electric starter system aimed at reducing drag and horsepower loss. As with the other bikes, we mounted a Dunlop D404 street tire on the rear wheel and ran the YZ450F on our in-house Dynojet dynamometer, where it spun out 50.09 horsepower at 9,650 rpm and 30.78 pound-feet of torque at 7,510 rpm. After the dyno runs were complete, we mounted up a fresh set of Dunlop MX33 soft-to-intermediate-terrain tires to ensure consistency in traction among the six bikes during the remainder of the test.
On the track, the YZ450F engine is both powerful and aggressive with heaps of bottom-end power, a strong midrange, and decent top-end. The engine’s ability to pull down low makes it easy to ride a gear high and lug it down low in the rpm. The new 49-tooth sprocket makes the bike a corner-exit weapon, but the bike revs out quickly. The Power Tuner app, with its multiple preprogrammed maps, helped counteract those tendencies, allowing us to choose a tune with more torque that gave the bike longer legs. The app also gives the rider the ability to create fuel and ignition timing changes with their phone and then upload them to the bike via the onboard Wi-Fi system. The clutch is very consistent with almost no fade, and the transmission shifts smoothly with minimal clutch input. There is some airbox noise, and the muffler isn’t the quietest of the bikes gathered here either, but we grew accustomed to both after a few quick laps.
Yamaha stuck with the tried-and-true spring fork while others turned to air a few years ago. This proved to be a wise decision, as the three other Japanese manufacturers have all abandoned air forks. Yamaha has always been praised for its excellent KYB Speed Sensitive System (SSS) fork and KYB shock. For 2019, the YZ450F has stiffer compression on both while retaining the same spring rates as the 2018 model.
The result is very close to race ready with the stock clicker settings, evidenced by the fact that each of our test riders made very few, if any, clicker adjustments during our two-day test. The YZ450F has the plushest and most forgiving suspension of all six bikes. It stays compliant throughout the the stroke regardless of the size of the impact, and soaks up braking and acceleration bumps with ease. The updated settings for 2019 are an improvement as both ends ride higher in the stroke and have more of a performance feel than last year. Even so, the bike runs a little bit lower in the stroke compared to others in the test. The YZ450F is unbeatable in terms of comfort, and shines brightest when the track gets rough.
Yamaha redesigned the front and rear wheel collars to have more rigidity in order to improve traction and front end feel. The other change is the use of 16-percent stiffer seat foam than the 2018 model. The 2019 YZ450F weighs in at a ready-to-ride weight of 248 pounds on our automotive scales, which puts it 2 pounds lighter than the Honda CRF450R and Suzuki RM-Z450.
The YZ450F is the most stable, predictable, and planted of all six bikes, especially in rough conditions. Those qualities give the Yamaha a bit of a heavier feeling overall and it sacrifices some nimbleness as a result. However, the suspension and chassis changes add up to a bike that corners better than it has since 2010 when Yamaha introduced the reversed cylinder head, rearward-slanted engine. That’s especially true when raising the fork in the clamps by 2mm up to 7mm. This helps with corner lean-in, adds additional front wheel traction, and doesn’t have any effect on the Yamaha’s excellent stability. Once in the corner, it’s easy to get back on the gas sooner because the bike steers more with the rear wheel.
The radiator shrouds and fuel tank are a bit wider than the other bikes, but the overall ergonomics package is an improvement. The updated seat offers a better rider position and makes it easier to move around on, yet remains comfortable. The seat does have a significant dip in it, and we would prefer a flatter, taller design.
It has a powerful engine that pulls exceptionally well in the low-end and midrange, the plushest suspension, the best stability in the class, and comes with the free Power Tuner app.
Why It Didn’t Win
It has a heavy feel, a wider gas tank and radiator shroud area, and the least agreeable ergonomics.