Not content with releasing all-new motocross machines in 2009, Kawasaki has refused to rest on its laurels by announcing a wide range of updates for its 2010 KX250F and KX450F.
Although the biggest news is probably what's not coming -- electronic fuel injection was expected on the 250, but that's been put on hold - there are still enough updates to keep the pressure on the opposition, including new high performance bridged-box bottom pistons for both machines, as used by Kawasaki's factory racers.
The lighter piston, which has a shorter skirt and piston pin, is claimed to boost power up top and on overrev, and is more durable. It's the first time the bridged-box bottom piston has been used in a volume-production machine.
The 450 is already a power freak, but revisions to the ECU settings have produced even more poke in the bottom end and mid-range.
The 250 and 450 also have new seats and thicker and wider radiators, which has necessitated new one-piece plastic shrouds. The steering stem and swingarm are also lighter.
The 450 has a new clutch that features a lighter pressure plate, better oil drainage and new friction plates with 75 percent more friction material.
The 450's Uni-Trak rear suspension has revised linkage mounts and ratios, and the Kayaba front end has altered spring rates and damping settings.
The 250 has Showa suspension, and there's now a low-friction titanium coating for a smoother fork action. The 250 also has revised damping.
The bikes have factory-style graphics, including black rims and fork guards.
Kawasaki Australia anticipates an August-September release for the KX450F and KX250F, with an arrival date(s) for the 2010 KX85 and KX65 are to be advised.
Pricing on all models has still not been announced.
For more information on Kawasaki motocross range, click here.
Meanwhile, Australian Motorcycle News (AMCN) is reporting in its latest issue (Vol 58 No 24) that Yamaha's YZ450F is set for a major overhaul in 2010.
AMCN obtained leaked details of the thumper, which is set to boast a reverse cylinder configuration. That is, the straight intake port will be mounted at the front of the cylinder, as will the airbox, while the exhaust will exit directly from the rear of the cylinder.
The new design should be a huge weight saver, especially the smaller bulk of the exhaust, and Yamaha will finally join Suzuki, Honda and Kawasaki with electronic fuel injection.
The YZ450F is also expected to get a new cylinder head, with four valves instead of five, and a new twin-spar aluminium frame and subframe. The suspension will also be revamped.
There is an official embargo on the 2010 Yamaha until late July.