Like so many other manufacturers, Kawasaki->ke299 started out 2016 by tweaking its biggest MX bike, the award-winning KX 450F. Already an accomplished model, the engineers focused on making it lighter and faster as they seek an edge in the battle for big-bike supremacy. Now that the summer is over and the 450F is back from fat camp, we can see exactly what Kawi has in store for us this year.

In short, it's almost an entirely new bike, one that Kawi hopes will bring more podium finishes and championships for themselves and their buyers. Toward that end, the factory trimmed a total of 7.5 pounds out of the frame, engine and transmission, and revised the mill to put out a bit more power. Rider feedback so far is good, but only time will tell how competitive this revised ride will be.

Continue reading for my review of the 2016 Kawasaki KX 450F.

Design

Kawi's KX 450F has in years past been something of a mixed bag. Widely regarded as a powerful bike that was very stable on the straights, it also had a reputation for being a tad massy and somewhat wooden in the corners. The factory set about rectifying that situation with a slim-and-trim frame that weighs in 3.1 pounds lighter than the 2015 skeleton. It flattened the fuel tank and narrowed the seat for plenty of room to shift around fore and aft as needed, and minimized the body panels, leaving just enough meat for the rider-to-bike contact areas. This lack of cladding leaves the bike looking clean, and provides plenty of access to the engine without the need to pull a bunch of plastic off first. The only non-contact panels act as a guard and air scoop for the twin radiators, so much like a teeny-bikini, the body panels leave little to the imagination.

Chassis

The engineers started their lightening project by trimming some fat from the frame. Perimeter side rails got whacked by 6 mm, dropping a pound and allowing for a narrower fit. The subframe and swingarm were also tweaked for strength and weight reduction, and the overall frame layout is meant to combat the obstinate cornering nature associated with this bike.

Some might say that the next bit is minor, but I feel is very important to mention; adjustable rider triangle. You can adjust both the footpegs and the handlebars so you can dial the bike in for your particular body style. I feel like this is an improvement over the general, one-size-fits-all attitude prevalent among most big manufacturers, and it may even be a selling point to riders at both ends of the spectrum. Though this isn't a brand-new feature, it lends a certain flexibility to the ride, and much like Launch Control, I expect to see this become a regular feature across the industry sooner rather than later.

Now for some really slick stuff. Kawi stuck a pair of Showa SFF-Air TAC (triple air chamber) inverted front forks on the 450F, and these forks are really something. They come with an inner air chamber used to control overall stroke, and an outer air chamber for bottoming resistance. A balance chamber manages the initial compression damping, and a screw adjuster allows you to tune up the rebound and compression damping. By replacing steel springs with pressurized air, the factory reduced weight and friction in the forks, making for a very smooth action. A Showa rear monoshock works with the Kawi Uni-Trak swingarm linkage, and comes with individually adjustable high-speed and low-speed compression settings. “Plush” is the word I hear most from test riders, but that's a relative term, and the suspension adjustments allow you to find your own plush zone.

Braking components got a boost too, with a 270 mm, petal-cut disc up front and 240 mm petal-cut disc in back. This is rather large for an MX bike, and the wavy edges help to dissipate heat and self-clean as they go roundy-round.

Drivetrain

The engine starts out life on a light note, with redesigned crankcases that shed 13 ounces right off the bat. A revised intake cam and sprocket drops another 1.2 ounces, and the new crankshaft balancer and drive gears drops an additional 3.2 ounces. The jug got set forward 8.5 mm, and the heads got ported and polished for low-resistance at the valves. Piston shape was refined a bit, and the Box-Bottom piston crown was relieved to match the new intake valve travel.

With a 96 mm bore and 62.1 mm stroke, it leaves the displacement right at 449 cc, right up against class limitations. Liquid-cooling carries heat from the water jacket to the twin radiators mounted to either side of the single downtube, where the body panels form a scoop to help force air over them. A 43 mm Keihin throttle body handles induction, and the exhaust comes tuned to increase low-end power and reduce noise emissions. Digital Fuel Injection (DFI) controls fuel delivery, which opens up some possibilities. You can get an FI Calibration kit that operates as a hand-held fuel-map adjustment device, or opt for the DFI Couplers that come with plug-and-play functionality for quick, trackside changes to engine power delivery. Finally, a Launch Control limits power through first and second gears to help you stick your holeshots; an important feature given the new power-to-weight ratio on this ride.

The five-speed tranny shaved almost 11 ounces out of its guts, and even the kickstarter dropped 2.6 ounces as part of the overall diet plan.

Price

MSRP on the 2016 450F is $8,799, just one bill more than last year, so all the R & D is largely absorbed by the company rather than passing it on to the customer. Destination and setup fees will apply, and may be variable.

Competitor

Kawi did a good job trimming some of the fat off its flagship bike, but it wasn't alone in this endeavor. KTM->ke1954, one of Kawi's main competitors across the dirt->ke295-sport spectrum, also lightened their big 450 SX-F as well. We will see how they match up on the track soon enough, but for now, let's look at how they stack up on paper.

First off, let's visit the scales. The Kawi KX 450F weighs in at 239.6 pounds wet (plus toolkit), and the KTM is a bit lighter at 224.6 pounds dry. That's a 15-pound difference, much of which will go away when the KTM is fully fueled and the toolkit on the Kawi is removed, leaving just a few pounds difference; not enough to overcome a skill differential to be sure.

As usual, I would love to compare performance number, but Kawi, much like the other Big-Four in Japan, is tight-lipped about such things. At a glance though, KTM pushes displacement to the absolute limit with 449.9 cc, 0.9 cc bigger than the KX. Not much to choose between the two, engine-wise.

Bottom line; there really isn't much of an edge with either ride, and at the end of the day it will come down to skill over hardware, every time.

He Said

“Whenever I see a light get lighter and more powerful, I worry about controllability. The Launch Control helps a bit out of the gate, and word on the street is the power is controllable and the bike is eager in the corners. I can't help but wonder what riders used to the older, heavier version will do with this light and agile machine. It looks to be an interesting year coming up.”

She Said

My wife and fellow writer, Allyn Hinton, says, "With the big manufacturers tightening their belts and trimming the fat, I expect to see even more excitement on the track. Lighter bikes with more power means more spectacular performances as long as they keep a balance between weight, power and control."

Specifications