Quickride: 2009 Kawasaki Kx450f

QuickRide: 2009 KAWASAKI KX45OF

ROUNDUP

IF YOU’RE A MOTOCROSS bike, you don't get to celebrate many birthdays. Before you have a chance to put more than a couple of candles on your cake, you’re railed off the track by a new-andimproved model and relegated to has-been status.

Such is the case with Kawasaki’s KX450F. Brandnew in 2006, the KX-F has undergone a wholesale re-do for ’09, including a reworked engine, a new frame and swingarm, improved front and rear suspension, and even new styling. Oh, and electronic fuel-injection, too.

It might, in fact, be the best dirtbike EFI we’ve ever tested. Though the system is battery-less, starting usually requires just one kick-important in the event of a fall. The key is a largerthan-usual generator that produces more current when kicking, along with the same 12-hole Bosch injector nozzle used on the ZX-10R sportbike; these allow the engine to fire after just three rotations of the crankshaft.

EFI on an MXer offers benefits that include precise throttle response, the ability to adjust for atmospheric changes and power delivery that can be optimized for different gears and throttle openings. But while the throttle response on the 450F is crisp, the transition from closed to open throttle is slower than normal. This is due to the use of a twoshaft, cable-controlled throttie linkage that opens the 43mm butterfly more slowly during the first 3/s of throttle movement than during the last 5/8. This, along with EFI, helps soften the hard bottom-end hit found on the 2008 model, allowing the rear tire to hook up better out of corners. This is good for the majority of riders but probably not so for most pros. The top-end hit is just as potent as on last year’s bike, though, and launches the 450 down the straights in a big hurry.

Other factors keeping the bike straight on those corner exits are the chassis improvements. The engine was rotated 3 degrees forward, the frame uses repositioned spars, a new swingarm has a 3mm-higher pivot point and the triple-clamps have 1mm less offset. These help the 450 feel lighter than the ’08 model during initial turn-in and allow the bike to hold its line with less of a tendency to stand up too soon. At 237 pounds, the new bike’s dry weight is identical to last year’s, despite the added hardware required by EFI, but that’s still 10 pounds more than Honda’s injected 2009 CRF450R.

That doesn’t mean the KX450F is uncompetitive.

It cranks out impressive topend power, shreds comers better than ever, has spot-on fuel mapping and is the easiest-firing fuel-injected 450 we’ve encountered. It’s even a lot more comfortable, thanks to a flatter, thinner seat. As a result, you can move backand-forth more easily without fighting wider body work.

At $7549, the KX450F is $550 more expensive than its predecessor; tack on another $200 if you want blacked-out Monster Energy graphics. We’ll have to wait for a comparison before we know how the Kawi stacks up against the competition, but one thing’s for sure: It’s the best KX450F ever built.

"With crisp EH and a new chassis, __ the KX is~~wi's best Thumper to date

Ryan Dudek