Yamaha moved the radiators, shrunk the gas tank, and redesigned the shrouds in an effort to slim down the bike to the tune of 16mm narrow at the shrouds and at the “pocket” of the seat. The new airbox and filter are still tool-less, now with one Dzus fastener for the cover and clips to hold on the filter. The seat is 8mm lower at the front and 19mm lower at the rear. Combined with the taller bar mounting, one test rider felt the bike was a little “choppered out” until he rolled the handlebar back a little. The bar bend is the same but the bar is lighter, and the rims (they are blue on the blue bike) are lighter too.
Yamaha put Wi-fi on the bike and its power tuner on your smartphone (just download the free app). The adjustment grid is now 4 x 4 instead of 3 x 3, and the tuning values can be adjusted to focus the tuning to a narrower rpm range. Fuel is adjustable richer or leaner up to 14 percent, and ignition can be retarded 9 degrees or advanced 4 degrees from stock. Riders can quickly pick from three stock maps, create their own maps, share maps, and try maps that the Yamaha test team shares. For paranoiacs worried about their bike getting hacked or a transmission interception, the app is password protected, only two phones at a time can be tied to any given bike, and the bike’s system must be powered up but with the motor off. The tuner also has a race log to organize your best settings.
Even the suspension got some updates. The fork’s cylinders and pistons are up 1mm to 25mm, and the mid-speed valves and pistons are updated. The shock’s subtank capacity is increased 30cc, and its spring is lighter in weight and one rate stiffer (from 56 to 58 N/mm). The fork rate remains at 5.0 N/mm.
With 450cc of displacement, a bike in this class can have too much power, and that was a criticism of the previous-generation YZ-FS for some riders—maybe not too much but “too much too soon.” The 2018 machine does a better job of making that horsepower more usable without making it less potent. Yamaha has smoothed not just the off-idle hit but also the full power delivery up through the rpm.
Nearly every rider commented the power down low was strong, but more importantly it was accessible and no longer abrupt or overly snappy. The smooth and tractable feeling continues through the revs, making the bike easy and fun to turn with the throttle in the flat corners and also meaning riders could rely only on throttle input and leave the clutch alone in corner ruts.
The overall character of the power still
retains some traditional four-stroke personality with a tractor-y feeling compared to some of the other bikes in the class. It’s one of those deceivingly strong engines where you might find yourself launching farther than the rpm suggested you would. The most usable portion of the powerband was the low to mid, yet some testers commented the bike needed to be shifted a lot for a 450, with first gear being especially short. Yamaha has held the top spot in suspension action and feel for about a decade, and blue shows no signs of making a misstep. Yes, the 2018 YZ450F has outstanding suspension.
Probably the best word used to describe the suspension feel is “buttery.” The Yamaha makes the small track imperfections disappear and gives almost a magic-carpet ride over the chattery stuff. More great news, many testers felt the bike needed no adjustments to make the suspension feel just right for them; the stock settings suit a wide range of riders.
There were, however, two pro-level testers who complained of a harshness transferred to their palms, with one saying he also felt a mid-stroke step in the fork. These same pros felt a sort of “bounciness” in the fork at corner entries. These two criticisms were almost lost, however, in the list of praises for the suspension feel, as most riders, heavy and light, novice to expert, felt the bike was plush and also handled the big hits amazingly well.
The YZ-F has a sit-in (rather than sit-on) feeling that allows the rider to feel a part of the bike; it’s more of a machine the rider charges around the track rather than finesses, manipulates, or manhandles. The previous YZ450F had a very big and sometimes uncooperative attitude; this new bike is much more eager to listen to the rider. It’s lighter feeling on the track, and some riders even said it had a 250-ish feel, though it still has some of that “significant” feel of the previous bike.
But the big YZ-F did draw some handling criticisms of headshake at corner entrances from a few testers, while others felt no trace of it. It was mostly limited to a twitchy front end under braking when entering high-speed corners. One pro tester had a big problem with this, but a sag change down to 107mm then going two stiffer on fork compression and four slower on fork rebound remedied the problem. Another lighter, fast tester cured the corner-entry twitchiness by going just three clicks slower on fork rebound. There was also a few mentions of a front end that wanted to climb out of ruts or just give a vague feel in corners.
Most riders felt they could put the bike right where they wanted on the track, with comments that it rolled well through the corners, that it had a calm, predictable nature, and that it had great stability on straights and jump launches. One pro rider even said the bike almost seemed to adapt to him and the track conditions, necessitating no suspension tuning.
All our testers felt Yamaha’s new slimmer bodywork was a great improvement, though some wanted it to be even thinner, and many felt the bike was slim and great while standing but once sitting to corner the shrouds pushed their legs out too far. One rider found the left header interrupted his grip on the bike, while another felt the bike’s sides had an overall slick feeling and would use grip tape if it were his personal bike.
The clutch was praised and the Yamaha is a clean-shifting machine, and the brakes were loved for being strong and easy to modulate.