TEN YEARS AGO TODAY! MXA’S 2014 KAWASAKI KX450F RACE TEST

A: You bet. The 2011-2014 KX450F engines are incredible. Their powerband is a thing of beauty. It is smooth down low, rolls on with authority and is the best all-around race engine of 2014. It doesn’t make the most power, but it has perfectly placed power. At 55.05 horsepower at 9000 rpm, the KX450F ranks third on the horsepower chart below the 2014 Yamaha YZ450F and KTM 450SXF. But is racability, it ranks first.

Every MXA test rider loves the KX450F powerband. It makes power where you need it and in ample enough doses to get the job done. And, best of all, if you don’t have a secret Swiss bank account to spend on aftermarket pipes, cams, maps or head mods. You won’t be at a disadvantage with the stock engine. If you want more power, switch to the white map plug-in. If you want less, go with the black one. The tunability is one of the best features of the KX450F engine package.

A: Things you need to know.

Footpegs. The KX450F footpegs are adjustable up and down. No MXA test rider moved the footpegs out of the stock position.
Bar mounts. If you move the bars to the forward mounting holes you can’t access the air valves on the Kayaba PSF air forks. MXA runs either Splitstream crossover air valves or Works Connection rotating valves ±to make it easier to get the air in.
Throttle tube. We loved last year’s 10mm longer Kawasaki grips, but Kawasaki went back to the 10mm shorter grips for 2014. Boo hoo.

Front brake. The stock front brake is no match for the KX450F. Invest in an oversize front brake rotor if you want to stop.

Chain guide. Order a T.M. Designworks Slide-N-Glide kit immediately because the stock chain guide won’t last as long as it takes UPS to get the T.M. Designworks parts to your house.
Plug-on maps. The KX450F comes with three plug-in maps—stock (green), mellow (black) and aggressive (white). On the dyno there was no perceptible horsepower difference between the stock and aggressive maps—on the other hand, the mellow map gave up one horse.

Horsepower everywhere. The MXA test rider were equally split on the green and white maps.

Gearing. We add one tooth to the rear sprocket to enable us to shift to third gear sooner. This maximizes the breadth of the powerband. We aren’t gearing it down to get more hit, just to get to the KX450F into a broader and easier to use gear quicker.

 

Clutch. Unfortunately the stock KX450F clutch pack cannot handle the mighty KX450F powerband. At the very least install stiffer clutch springs, but if you intend to keep your bike for a long time get a complete Hinson clutch.

Backfire screen. The KX450F’s wire screen is incredibly restrictive. We remove it.
Launch Control. As rule of thumb the MXA test riders use this mantra, “Soft dirt—no Launch Control. Hard dirt—Launch Control.” Contrary to popular opinion, Launch Control does not affect the horsepower below 7000 rpm.Why not? Because nobody launches off the starting line with the engine at idle. Nope. They rev it up to eight grand and dump the clutch. So, Launch Control progressively makes less power as the rpm climbs. The object of Launch Control is to lessen wheelspin in second gear. Once you shift to third gear Launch Control is deactivated.

Q: HOW DOES THE 2012 KX450F HANDLE?

A: Kawasaki didn’t make any headway in improving their handling for 2014 because they didn’t make any changes to the chassis or suspension. We can live with the KX450F’s handling, but by no means is this jumbo-size frame in the running for the best handling bike of 2014. We never really liked its tendency to stand up in the center of corners and wallow under acceleration, but we forgive a lot of its peccadilloes because the powerband covers up a lot of flaws.

Q: WHAT DID WE HATE?

A: The hate list:

(1) Brakes. These old-school brakes won’t stop 239 pounds of runaway locomotive.

(2) Weight. For the ninth year running. It’s too big, too tall and too heavy.

(3) Sound. This is the loudest bike on the track. It makes an ear piercing 120.6 decibels on the AMA two-meter-max test. It did pass the SAE 94 dB test (conducted at 4500 rpm). It is important to note that local and amateur racers don’t have to comply with the two-meter-max standards—those are reserved for the 660 AMA Pro license holders.

(4) Rear brake pedal. If you want to run the rear brake pedal low (as many old school racers do), you have to hacksaw off some of the plunger’s threaded rod.

(5) Rear axle nut. We remove the cotter pin and axle nut, and replace them with a self-locking Honda axle nut. It’s a cheap fix and makes life easier.

(6) Shifting. Don’t rush it no matter how big a rush you are in.

Q: WHAT DID WE LIKE?

A: The like list:

(1) Tires. We liked the Bridgestone 403/404 tires.

(2) Adjustable maps. You gotta love a bike that comes with three different powerbands—that can be changed in 30 seconds.

(3) Launch Control. You can use it or ignore it, but it adds a new dimension when the situation arises. And that situation is a concrete or hard-pack starting line.

Q: WHAT DO WE REALLY THINK?

A: We think that the suspension is acceptable (although the forks are borderline), the handling passable, the shifting suspect, the clutch weak and the brakes mediocre, but the powerband is superlative. In order to get our hands on that luscious powerband, we have to make a few compromises in the other areas.



MXA KAWASAKI KX450F SETUP SPECS

This is how we set our Kawasaki KX450F up for racing. We offer it as a guide to help you find your own sweet spot.

KAYABA PSF FORK SETTINGS

The big news revolving around the KX450F and CRF450 for the last two models years has been the Kayaba Pneumatic Spring Forks (PSF). Air forks are an old concept—one that had been buried and forgotten for over 30 years. However, air is back and more importantly, the new PSF forks are better than what Honda and Kawasaki had before them. Not a lot better. Not anywhere as good as Yamaha’s Kayaba SSS forks, butthey have a nice feel when the air pressure is set to the desired psi. It is important that riders spend more time with the clickers and less time going up and down on air pressure. The air is just a replacement for the coil springs and, once it is right for the conditions, it is right. We recommend this fork setup on the 2014 Kawasaki KX450F:

Spring rate: 35 psi

Oil height: 245cc

Compression: 11 clicks out

Rebound: 19 clicks out

Fork leg height: 5mm up

Notes: When the air pressure is wrong, you will recognize it right away. Too little air feels like you have a flat tire, while too much air will result is a serious spike at the end of the stroke when the pressure ramps up in accordance with Boyle’s Law. We started at 35 psi, but that is the cold air number. Once the bike was ridden, the air pressure went up as much as 4 psi. Since you can’t wait for the forks to cool down at the races, if the pressure climbs from 35 psi to 38 psi, but you want them softer, just remove 1 psi to the 38 to make it 37 psi. Theoretically, going up 2 psi is the equivalent of going up one spring rate (from 0.47 to 0.48). Tuning is complicated by the ramp up effect. Thus, if you add fork oil or air pressure to make the forks a little firmer, they will be very harsh at the end of the stroke.

KX450F SHOCK SETTINGS

As for the KX450F shock, the overall setup is decent, and the 5.5 kg/mm shock spring covers a wide range of test-rider weights. We recommend this shock setup on the 2014 Kawasaki KX450F (stock specs are in parentheses):

Spring rate: 5.5 kg/mm

Hi-compression: 2 turns out (1-3/4 turns out)

Lo-compression: 10 clicks out (8 clicks out)

Rebound: 14 clicks out (19 clicks out)

Race sag: 100mm

Notes: We preferred the feel of the longer Pro Circuit pull rods because they lowered the rear end, but more importantly, they stiffened the initial part of the shock’s stroke to lessen the KX450F’s tendency to wallow under acceleration.

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