2012 Kawasaki KX450F | First Ride

Prepare for Launch

By Karel Kramer, Photography by Karel Kramer

First it was mega-dollar supercars, then cutting-edge superbikes, and now launch control has come to dirtbikes on the 2012 Kawasaki KX450F.

In the case of the Aprilia RSV4 Factory APRC SE that won Motorcyclist's "Class of 2011" sportbike comparison (MC, August), launch control means holding the throttle wide-open, dropping the clutch and letting the electronics take care of everything, actively preventing wheelies and wheelspin to allow the quickest possible start.

On the KX450F, it's a bit less sophisticated. Hold down the button on the left side of the handlebar and the integrated light blinks red, alerting you that launch-control mode has been enabled. The DFI (Digital Fuel Injection) electronics then maximize acceleration by minimizing wheelspin through a predetermined, and passive, map. As soon as you shift into third gear, the standard map is restored.

But wait, there's more! The ECU contains three maps: standard, soft and hard (referring to track conditions). A coupler by the right side of the steering head connects the wires to tell the ECU which map to run. Each bike comes with the standard coupler installed, plus two more for the other maps. To make a change, simply pop the coupler out and replace it with the one you desire-no laptop required as on previous KXs. An optional FI calibration kit allows for unlimited tuneability, or you can load in any of seven preset maps.

As you can imagine, the addition of all this techno-wizardry had the Team Green press corps popping verbal wheelies. That's all well and good, but there's more to the 2012 KX450F than electronics. Nearly every technical aspect was trimmed, tuned or upgraded. With rare exception, each change is measured in increments invisible to the naked eye, yet together they effectively raise the bike to the level of an all-new model.

Inside the engine are a lighter box-bridge piston with a thinner compression ring, a higher-lift intake cam and some welcome transmission changes. Oddly, since it is used so seldom, first gear is physically 20 percent wider (and thus stronger), and the gears have switched from three dogs/slots to four re-angled dogs/slots on each. A shorter shift fork and a 3mm-longer shift lever shorten the shift throw to ease shifting.

The exhaust pipe has a shorter, tapered head pipe, a tapered mid-pipe and an 80mm-shorter muffler to help centralize mass. Those changes are mostly visible, but Kawasaki was sneakier with the aluminum frame. The perimeter rails were tucked in 2mm to narrow the bike, while the frame spars are stiffer near the swingarm pivot, but have fewer and smaller internal braces higher up. The frame changes work with revised suspension settings, new triple clamps and slimmer link arms to give the bike better handling and bump-impact feel.

Wrapping the chassis is what Kawasaki calls "minimalist" plastic. It's trimmed and tucked with flush seams, the gas tank carries its 1.6 gallons lower and the seat feels more level.

But never mind the list of technical features, what matters is how the new KX450F performs on the racetrack. And to find that out, Kawasaki invited the moto-press to world-renowned Red Bud in southern Michigan, which hosts an AMA national each July 4th weekend. The challenging track was deeply prepped with power-robbing loam and steep climbs, but the KX was more than up to the task. With the standard coupler, the power was snappy and aggressive yet controllable. With the hard coupler installed the rear tire felt more connected to the track, and acceleration out of turns was excellent. Revving the bike, the boost was plentiful, but not brutal. With the soft coupler plugged in the bottom wasn't as smooth and connected, but the engine boosted hard in the middle and pulled like crazy on top.

Naturally, as soon as we got a feel for the bike, we headed to the start straight to test the launch control. A Kawasaki rep claimed, "You can forget what you know about starts, hold it wide-open and dump the clutch," but we found that wasn't exactly true. For sure the launch-control mode made starts far more consistent and controlled, but if you held the throttle wide-open, you'd still loop it!

The 2011 KX450F had arguably the best suspension in its class. And while the actual suspension components are unchanged, they are high-end units, with the only fork in the class boasting a DLC (Diamond Like Coating) on its inner tubes. Upgrades to the internal settings combined with the aforementioned chassis changes make for a bike that isn't upset by bumps-and the track had plenty of those by the end of our two days there! The action is plush-yet-controlled and the clickers make a difference you can feel. Bottoming resistance was good even for heavier riders, and the stock springs worked under a wide range of rider weights and skill levels.

Once we were happy with the handling and had settled on the hard map as our favorite, we explored the KX's ergonomic adjustability. New on the 2012 model is a top triple clamp with a total of four handlebar positions. The rubber-mounted bar dictates that the adjustments are coarser than those of other brands, but they're welcome nonetheless. We settled on the bar mounts bolted in the forward position with the offset clamps turned to the rear.

Kawasaki also cleverly gave the frame two sets of footpeg mounts. Moving the bolts to the second set of holes lowered the pegs by 5mm. We found the extra legroom welcome as it made it easier to get up off the seat. Combined with the forward bar mounts, the stretched-out cockpit was well suited to riders over 6 feet tall.

The KX450F is a motocrosser Kawasaki can be proud of! It has better-than-average stability, handles airtime with ease, its suspension sucks up most anything in its path and it requires less effort to change direction than before. Riding on an unfamiliar track without any competing models (or even a 2011 KX450F) on hand makes it difficult to be absolutely certain, but the steering precision and ability to track into small ruts still feels a little behind the best in the class. Beyond that, though, the KX450F is a masterwork of adjustability combined with tour de force engine performance. That should make it very hard to beat in 2012.

tech SPECS

EVOLUTION
A late entry in 2006, the KX450F has been consistently upgraded to the point that it won the 2011 AMA Supercross Championship.

RIVALS
Honda CRF450R, Husqvarna TC449, KTM 450 SX-F, Suzuki RM-Z450 and Yamaha YZ450F.

Tech

Price: $8399
Engine type: DOHC, 4v
Displacement: 449cc
Bore x stroke: 96.0 x 62.1mm
Compression: 12.5:1
Fuel system: EFI
Clutch: Wet, multi-plate
Transmission: 5-speed
Claimed horsepower: na
Claimed torque: na
Frame: Aluminum perimeter
Front suspension: Kayaba 48mm inverted fork with adjustable compression and rebound damping
Rear suspension: Kayaba shock with adjustable spring preload, high/low-speed compression and rebound damping
Front brake: Nissin two-piston caliper, 250mm disc
Rear brake: Nissin single-piston caliper, 240mm disc
Front tire: 80/100-21 Bridgestone M403
Rear tire: 120/80-19 Bridgestone M404
Rake/trail: 26.9°/4.4 in.
Seat height: 37.6 in.
Wheelbase: 58.3 in.
Fuel capacity: 1.6 gal.
Claimed curb weight: 249 lbs.
Color: Lime Green
Available: Now
Warranty: na
Contact: Kawasaki Motors Corp. USA
9950 Jeronimo Rd.
Irvine, CA 92618
949.770.0400
www.kawasaki.com

VERDICT
For 2012 it may be the other brands that are green-with envy.

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