Okay, so you wanted some news on the KX450F announced by Kawasaki a few months ago. Well, that bike will not be a 2005 model. Expect it for 2006, however, and perhaps as an “early release” model.
The big news from Kawasaki in motocross bikes is the all-new KX250. That’s right, like Yamaha, Kawasaki has not given up on two strokes. The KX250 has a new frame, new suspension, and a new engine. New enough for you?
Beginning with the frame, it is narrower, features a steeper steering rake (reduced from 27 degrees to 26 degrees), and has revised “stiffness balance”. A new swingarm with beefier construction (for improved stability). Ground clearance is improved with higher footpeg and rear brake pedal, as well as the narrower frame construction (already mentioned). Other ergonomic changes include revised handlebar bend (still steel, apparently) and 10mm higher seat (which is also flatter). The seat cover has a grippy top and smooth sides.
Both the clutch cable and the throttle cable are said to be smoother and more slippery (requiring less effort), and the clutch now features an adjustment on the perch. Also new is the front brake lever that, along with new front brake pad material, is said to offer better feel and performance.
The Kayaba forks are now a twin-chamber design with lower friction fork seals. Fork tubes are still 48mm for 2005. The rear shock features re-designed linkage ratios.
You can see the “more vibrant than ever” lime green bodywork in the photos. The biggest news is the engine, however. The 249cc two-stroke sits more upright (5 degrees from vertical versus 10 degrees last year). Virtually everything about the motor appears to be new. The upright cylinder allowed a longer exhaust port, and better angles for intake and reed valve. Along with an appropriately revised air intake, throttle response is said to be significantly improved, as well as power.
A new power valve design works with revised exhaust ports and expansion chamber for improved power, as well.
Revisions to the transmission are claimed to improve feel, while a new water pump, combined with revised coolant flow around the cylinder, increases coolant circulation to keep heat from reducing engine performance. The crank cases are new, requiring new sprocket cover, governor cover, inner/outer clutch covers, and water pump cover. The generator cover is now magnesium instead of plastic.
Radiator core length has been increased (from 220mm to 240mm) for improved cooling performance. The ignition system has also been upgraded, with increased condenser capacity. Ignition timing has been changed to suit the new motor’s power characteristics. The ignition coil is more compact and lighter. Spark is fed through a new, shorter spark plug that eases maintenance and weighs less.
Handlebar mount positions are 8mm wider this year to provide firmer support, while a new front rim and redesigned rear rim reduce unsprung weight.
The hole on the top of the gas tank has been increased from 37mm across to 46mm for “easier fueling”.
We have not seen any claims from Kawasaki regarding overall weight reduction for the new KX250, and the bike continues to feature a steel frame (with aluminum subframe). Price and availability date are unknown at this time.
Take a look at our article earlier this week regarding the Suzuki RM-Z250 for a summary of changes to the similar 2005 KX250F. Kawasaki made minor changes to the other motocross bikes in its line-up.
