2006 Kawasaki KX250F
Two years after its initial release, we decided to completely revamp our 125cc-class 4-stroke motocrosser. For 2006, we gave the KX250F a serious increase in power and all-new aluminium perimeter frame like that of the all-new KX450F.
If you are serious about racing, then we believe that you will find the new machine is a highly competitive package that will give you an edge on the track. While mid- to high-level riders will be the ones best able to fully appreciate the new KX250F's racing potential, even novice riders will notice the smoother power delivery at low rpm and the improved rear wheel traction.
Neck and neck, you come out of the turn and snap the throttle wide open. Revs climbing higher and higher, your rival starts to fade while your motor is still pulling...
We are confident that you will be pleased with the improvements we made to the new KX250F's engine. The new bike has significantly more power than the '05 model. The power is best at high rpm.
We also smoothed out the torque curve, and gave the new KX250F as wide a powerband as possible, extending it way into the over-rev.
To further increase the overall racing performance of the engine, we paid a lot of attention to small details in order to increase the engine's reliability.
When the gate drops your bike catapults forward with the horde of highly tuned machines.
Jostling for position going into the first corner usually an experience just short of an all-out
brawl, a quick glance shows that you're alone.
The secret to traction is the combination of usable torque and a good rear suspension set-up. We tuned the engine so that the torque curve follows the limit of running resistance for as long as possible. (Unchecked, engine torque can exceed this limit, resulting in wheel spin, which does nothing to help your forward momentum.) When we first started developing the new aluminium perimeter frame, we set the centre of gravity and key chassis dimensions (swingarm pivot, output sprocket and rear axle locations) so that the rear tyre would drive the bike forward (instead of causing it to squat). The engine itself has a very upright orientation, which helps with mass centralisation.
Then, with the help of extensive rider feedback, we determined the rear suspension settings (link ratios and rear shock absorber tuning) that would best complement the aluminium frame's rigidity balance.
Flying over the back triple you land next to another rider. But while his bike seems to "freeze" for an instant as if collecting its wits on impact, you're already shooting forward.
With years of experience designing high-tensile steel perimeter frames for our KX racers, for the new KX250F we combined this know-how with the latest technology to design an all-new aluminium perimeter frame like that of the KX450F. The slim frame is composed of a combination of forged, extruded and cast parts. Once we determined the best balance of torsional and longitudinal rigidity for high-level riding, we added complementary front and rear suspension. The handling characteristics from the basic chassis and the settings we have chosen were selected to allow fast riders ride faster.
But we did not stop there. We added a number of works-style components, like high-performance petal disc brakes and a Renthal handlebar. Even the bodywork is purpose-built to put the rider in a position to ride fast - not just in bursts, but for the entire race distance.
The KX250F's key sales features can be summarised as follows:
Race-oriented Engine Characteristics - 249 cm3 liquid-cooled, 4-stroke Single tuned for high-rpm performance and high reliability.
Superior Rear Wheel Traction - chassis dimensions (set for anti-squat) that maximise the wide spread of available torque, and rear suspension link ratios and shock damping settings determined from extensive rider testing result in superb rear wheel traction.
Race-oriented Chassis Balance and Settings - all-new aluminium frame, suspension settings set to suit high-level riders, petal disc brakes, numerous works-style components.
Engine Type - Liquid-cooled, 4-stroke Single
Displacement - 249 cm3
Bore and Stroke - 77.0 x 53.6 mm
Compression ratio - 13.5:1
Valve system - DOHC, 4 valves
Fuel system - Carburettor: Keihin FCR37
Ignition - Digital AC-CDI
Starting - Primary kick
Lubrication - Forced lubrication, semi-dry sump
Transmission - 5-speed, return
Final drive - Chain
Primary reduction ratio - 3.350 (67/20)
Gear ratios - 1st: 2.142 (30/14), 2nd: 1.785 (25/14), 3rd: 1.444 (26/18),
4th: 1.200 (24/20), 5th: 1.052 (20/19)
Final reduction ratio - 3.692 (48/13)
Clutch - Wet multi-disc, manual
Frame Type - Perimeter, aluminium
Wheel travel - front: 315 mm, rear: 310 mm
Tyre - front: 80/100-21 51M, rear: 100/90-19 57M
Caster (rake) - 27.7°
Trail - 119 mm
Steering angle (left/right) - 42°/42°
Suspension - Front: Type, 47 mm upside-down twin-chamber telescopic fork
Compression damping 16-way Rebound damping 16-way, Rear: Type, New Uni-Trak
Compression damping 13-way (low-speed), 2-turns or more (high-speed)
Rebound damping 17-way Spring preload Fully adjustable
Brakes - Front: Type, Single semi-floating 250 mm petal disc
Caliper Dual-piston, Rear: Type, Single 240 mm petal disc Caliper Single-piston
Overall length - 2,160 mm
Overall width - 820 mm
Overall height - 1,270 mm
Wheelbase - 1,469 mm
Ground clearance - 372 mm
Seat height - 960 mm
Dry weight - 92.5 kg
Fuel capacity - 7.2 litres
Maximum power - 32.0 kW {43.5 PS} / 11,500 rpm
Maximum torque - 29.9 N·m {3.05 kgf·m} / 9,000 rpm
The specifications mentioned here apply to and have been achieved by production models under standard operating conditions. We intend only to give a fair description of the vehicle and its performance capabilities but these specifications may not apply to every machine supplied for sale. Kawasaki Heavy Industries, Ltd. reserves the right to alter specifications without prior notice. Equipment illustrated and specifications may vary to meet individual markets.
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