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!
Pressing and holding this button on the left side of the KX450F’s handlebar engages launch
These are the couplers used to alternate between the three engine maps. They’re literally
Kawasaki cleverly equipped the KX with four bar-mounting positions and two footpeg locatio