Click photos to enlarge.
They make great desktop images.
– 2011 Kawasaki KX 250F
2011 Kawasaki KX 250F
More AMA Lites Championships than any Motorcycle in History!
It’s an old refrain: The factory guys get all the good stuff. Their bikes are faster, lighter and just plain tricker than the motocrossers you can buy off the showroom floor. There’s some truth there. But that’s changing. The gap between production and factory-prepped motocrossers has never been narrower. And with the introduction of Kawasaki’s massively reworked 2011 KX™250F, that gap just shrank a little more.
All told, there are nearly 30 upgrades to the new KX250F, all of which reflect the stunning level of testing and development happening behind the scenes at Kawasaki’s R&D and race teams. And Kawasaki does this for one reason: To put you on the fiercest, most capable motocrosser in the industry.
When reworking the new KX250F, engineers started with what’s arguably already the gold standard in 250-class racing – the 2010 KX250F. Just ask Christophe Pourcel and Jake Weimer, who won the 2010 AMA East and West Lites titles, respectively, on their Monster Energy™/ Pro Circuit / Kawasaki-backed KXs. Or the long list of enthusiast magazine shootouts that picked the 2010 KX250F as the best motocrosser in its class.
For 2011, the goal was an even faster and more ridable KX250F. On the more powerful side of the equation are loads of engine modifications, all of which have made the latest KX an absolute corner-to-corner screamer. The big news is the addition of Digital Fuel Injection (DFI®) that not only helps produce stunning – and more useable – power, but also makes tuning a much easier proposition. The system, basically identical to the one fitted to the 2011 KX450F, automatically adjusts to suit track and climate conditions, and offers consistent fuel metering and response even when the going gets rough, such as when landing off jumps or slamming through the whoops. The simple and highly efficient DFI system incorporates a compact and lightweight Electronic Control Unit (ECU), a 43mm throttle body, a lightweight aluminum fuel pump and an ultra-fine atomizing injector. Set at a 45-degree angle for optimum mid-range power, the injector precisely metered fuel directly into the intake tract for smooth power delivery and highly accurate engine response throughout the entire rpm range. The 250F’s injector actually flows more fuel than the 450F’s unit due to the 250F engine’s higher speeds, while airflow through the system is actually higher than through the 2010 model’s carburetor setup.
Designed specifically for motocross, the KX250F’s lightweight DFI system requires no battery; the engine can be started within three rotations of the crankshaft using only the electricity generated through the initial stroke of the kickstarter. What’s more, an optional ECU Setting Tool allows racers to select from several different ECU data maps, or fine tune a custom map that alters fuel injection and ignition timing to suit different tracks and conditions. The tool can also be used as a data logger, recording up to six hours of data, including engine rpm, degree of throttle opening, coolant and air temperatures, ignition timing, fuel adjustments, gear position and system voltage.
You’ll find more significant changes farther downstream, such as higher compression – now 13.5:1 vs. 13.2:1 – via a modified cylinder and changes to the top of the exclusive Bridged-Box Bottom piston. The intake camshaft now produces higher valve lift, while the intake valve spring is stronger to handle the extra load. The crankshaft’s rotational inertia has been slightly modified to better match the new engine’s characteristics, while a slightly longer spark plug design – and a new coil offering a hotter and longer-duration spark – improves combustion performance. Transmission and final-drive ratios have been altered slightly to match the engine’s newfound response, and a modified shifting mechanism allows you to access those speeds more easily and smoothly. There’s 10% more air-cleaner duct volume for better breathing, and on the exhaust side, a longer head pipe gives the engine a touch more low-end power, while a higher-volume muffler assembly lowers noise to comply with the 94 db AMA Pro Racing limit, while retaining optimum power production up top.
The chassis has been massaged every bit as thoroughly as the engine, with Kawasaki’s new Separate Function Fork (SFF) leading the list of changes. Unlike a conventional fork design, where each fork leg handles both springing and damping, the SFF separates spring and damping functions for improved performance, 25 percent less friction, lower weight and easier adjustability. The right leg accommodates the spring side of the equation, incorporating a larger main spring/rod assembly than traditional forks, plus a small amount of oil for lubrication. Spring preload is now adjustable via a blue-anodized adjuster on the right leg’s cap. The left leg handles damping duty, with only its cartridge damper assembly and fork oil inside the tube. Rebound and compression damping are adjustable on the fork tube. In addition to the natural reduction in friction provided by the SFF design, the KX250F’s inner fork tubes are titanium nitride coated to reduce friction. Lower friction and better overall fork action are keys to the new fork’s performance, and they are traits you’ll appreciate the first time you charge into a bump-infested corner at speed. Fork offset has also been reduced by a full millimeter for lighter handling and quicker steering response.
Out back, the rear shock incorporates revised damping settings that more closely match the SFF’s performance. The result is even more wheel and chassis control while ripping across a set of whoops or shrieking through that fast, rutted corner leading onto the front straight. Like the KX450F, the new 250F gets a reworked seat with grippier material along the sides for improved rider grip while standing when the action gets hot and heavy.
The rest of the package includes the same top-tier components that have put the KX250F atop the podium for years. The KX250F’s aluminum perimeter frame, with its lightweight blend of forged, extruded and cast parts, has the chassis balance, rigidity and durability experienced riders want and need, and locates the engine, rider and pivot points where they perform best.
Designed with rider ergonomics foremost in mind, the KX250F’s bodywork offers riders a slim interface and a natural positioning that make going fast a simple affair. The sleek bodywork components include one-piece plastic shrouds and side number plates. The upgraded seat provides excellent seated grip and rider mobility, and features firm urethane foam to hold its shape longer. Chassis protection bits include the large, resin skid plate, rear caliper guard and a redesigned chain guide with approximately 2.5 times more durability than the 2010 unit.
The KX’s 249cc, liquid-cooled, four-stroke engine is a veritable powerhouse, and features an electrofusion cylinder treatment on the cylinder bore, a crankshaft balance factor of nearly 60 percent (on par with Pourcel and Weimer’s factory racebikes), for reduced vibration and smoother power delivery, a highly durable – yet slick-shifting – transmission, stronger-than-ever crankcases and a level of reliability that’ll keep you out there and on-track all season long. It’s been rated the best engine in its class by various magazine editors, and you’ll understand their thinking after your very first ride.
The rest of the KX250F package is every bit as impressive as the engine and chassis. Aside from the sort of fit and finish you expect from Kawasaki, there’s also a premium-quality Renthal aluminum handlebar included standard, black alumite-coated aluminum wheels that are both light and strong, a ribless rear hub and butted spokes that further reduce unsprung weight, and factory-style graphics that finish things off nicely and highlight the KX250F’s amazing on-track abilities.
Racers who ride their KX250F at designated events are eligible to receive support from Team Green, Kawasaki’s amateur racing support program. Each year, Team Green™ provides regional support vehicles and highly trained technicians at more than 100 events throughout the United States, offering technical information and assistance to those who race Kawasaki products. Kawasaki also offers a comprehensive contingency program for amateur and professional riders who place well at designated events.
Kawasaki KX 250F model Highlights
Details & Features
At a Glance…
– New Digital Fuel Injection (DFI) system
– New Showa Separate Function Fork (SFF) divides spring and damping functions; springing in the right leg and damping in left provide less friction, better performance and easier adjustability
– Increased engine performance via higher compression and exhaust/intake changes
– High-performance piston featuring Bridged Box-bottom design
– Stainless steel exhaust features longer header section and larger-volume muffler
– Revised suspension settings front and rear aimed at race-experienced riders
Higher Performing, High-revving Engine
– 249cc, liquid-cooled, four-stroke, four-valve, single-cylinder DOHC engine delivers hard-hitting power across the rpm range
– Modified intake valve timing and cam profile for increased valve lift improves high-rpm power production
– Intake valve spring tension increased to control more radical cam timing
– Digital Fuel Injection (DFI) system allows consistent fuel delivery, quick starts and easy adjustability
– Engine tuned to achieve the widest possible torque band to maximize traction through a greater percentage of the rev range
– Race-experienced riders able to harness high-rpm performance that extends way into the over-rev
– Sprocket-style chain drive roller helps reduce the effect of driveline lash and engine braking for smoother and faster corner entries
– Crank web design features a balance factor on par with the factory racers for reduced engine vibration, smoother power delivery and increased performance in the mid-high rpm range
Digital Fuel Injection (DFI) System
– Same basic system that’s fitted to the KX450F
– 43mm throttle body assembly with 20 percent higher-flow injector than the KX450F’s injector
– Intake airflow is higher than on carburetor-equipped 2010 model
– Progressive throttle link; opens more quickly after 3/8 open position
– Simple and efficient system: No battery, fuses or relays
– Improves engine response across entire rpm range
– Offers easy engine starting
– Prevents engine hesitation after landing from jumps and other high-impact situations
– Optional Calibration Kit allows easy tunability
– Optional FI Indicator Light allows the DFI system to communicate diagnostic information
Bridged Box-bottom Piston
– Light and strong piston shares same design as the factory racers, with a revised crown for higher compression. Also features fully flush internal bracing
– Short piston pin reduces reciprocating weight
Lightweight and Efficient Top End
– Lightweight, highly rigid, titanium 31mm intake and 25mm exhaust valves reduce reciprocating weight and offer high-rpm reliability
– Ultra-light valves have extremely thin valve stems on par with those found in supersport machines; intake valves feature thick heads for increased strength
– Intake ports designed for peak performance at all rpm, especially in the high-rpm range
– Special coating applied to intake port cores during casting gives the intake ports extremely smooth surfaces and optimum intake efficiency across the rev range
– Silicon-coated head gasket provides excellent sealing
Enhanced Durability and Reliability
– Electrofusion treatment on cylinder bore improves surface oil retention, while the molybdenum coating on the cylinder bore surface helps resist scorching, further contributing to durability
– Wide big-end bearing features a thick copper plate on its cage and a long crank pin for increased reliability
– Oil pump rotors offer a high degree of reliability and durability; a large feed pump rotor maximizes oil flow, while a smaller scavenge-pump rotor reduces mechanical losses
New Stainless Steel Exhaust System
– Stainless steel construction offers extra durability
– Longer header pipe section for improved low and mid-range response
– Higher-volume muffler assembly quiets emissions to 94 dB noise regulations while retaining power production
– Joint between pipe and muffler offers excellent sealing, while a rubber damper collar on the rear silencer mount equals serious durability
Efficient Cooling System
– Thick and wide radiators are strong and offer excellent resistance to mud buildup while providing superb cooling performance
– Cylinder head water jacket routes coolant to the front of the cylinder head for even cooling
Transmission and Shifting Reliability
– Third and fourth input gears have large dogs to help prevent wear
– Revised ratchet and lever angle for more positive shifting
– Revised internal ratios for second and fourth gear better match new engine power delivery
– New 50-tooth rear sprocket helps capitalize on the engine’s torque delivery
– Strong, beefy crankcases feature additional material around the engine mounts to help increase long-term durability
– Clutch cable holder is integrated with the crankcase for accurate feel at the clutch lever
– Scavenge oil filter screen can be accessed without splitting the crankcases, facilitating easier maintenance
– Utilizes a low-rigidity steering stem for lighter handling
– The KX250F’s slim and lightweight aluminum perimeter frame is composed of forged, extruded and cast parts
– Center of gravity and key dimensions such as swingarm pivot, output sprocket and rear axle locations designed to increase forward drive with minimal rear-end squat
– Upper engine mounts on head cover sides increase overall rigidity
– Revised race-oriented suspension damping settings optimize front/rear balance
– New Separate Function Fork (SFF) separates springing and damping functions for less weight, better performance, less friction and easier adjustability
– Fork now allows external spring preload adjustability
– Super-hard titanium coating on the outer surface of the inner fork tubes reduces friction and improves suspension action. The increased surface hardness also helps prevent scratches and tube damage
– Friction-reducing Kashima Coat treatment on the inside of the outer fork tubes contributes to smoother suspension action
– Wrap-around fork tube guards provide greater protection for the inner tubes
– Revised shock damping settings offer increased absorption performance and greater stability on corner entry thanks to reduced rear-end kicking
– Features Kashima Coat on the inside of the shock reservoir for reduced friction and smoother suspension action
– Rear shock features dual compression adjustability, allowing high-speed and low-speed damping to be tuned separately
Superior Rear-wheel Traction
– Swingarm features optimum internal bracing and flex characteristics for improved cornering performance
– Alloy swingarm uses a cast front section, tapered hydroformed spars and forged chain adjusters
– Uni-Trak® rear suspension system mounts the suspension arm below the swingarm, allowing more rear suspension stroke and precise tuning
– Linkage ratios for the Uni-Trak rear suspension match rear shock damping settings to achieve maximum rear wheel traction
– Bodywork components offer the rider a slim interface, making it easy for racers to feel comfortable and go fast
– Formed using a double-injection molding process, the two-tone shrouds offer a slim design
– Side number plates also two-toned and contribute to the slim package
– Right side panel has an added passageway to help cool the silencer
– Frame is wider at the ankles to offer better grip and narrows near the bend below the seat to allow a slim riding position
– Slim seat features firm urethane, which keeps its original shape longer
– Seat has a slip-resistant top and side surface for good grip when seated and while standing
– 50mm wide (front-to-rear) footpegs offer superb grip and feel at the pegs
– Clutch cable boot features a large quick adjuster, making it easy for riders to adjust play in the clutch cable while on the fly
– Throttle grip has a one-piece collar that provides additional stability during throttle operation
– Lightweight short-length grips feature a pattern designed to provide excellent grip
– Black alumite-coated rims, just like the factory racers
– Lightweight rims offer maximum strength and weight savings
– Thick and rigid front fender
– Rear brake pad material offers powerful braking performance
– Front and rear petal brake discs help reduce unsprung weight, and the wave shape helps clean the brake pads for more efficient braking performance
– Rear caliper guard protects caliper from damage
– Ribless rear hub and butted spokes further reduce unsprung weight
– Renthal aluminum handlebar is standard equipment
– Factory-style graphics complement the KX250F’s highly tuned performance
– Large front brake lever boot offers increased protection against debris
– Newly designed and more durable chain guide utilizes a thicker wear pad for longer life
– Large resin skid plate offers great protection with minimum weight
– Optional DFI Calibration Kit allows custom tuning
– Optional FI Indicator Light allows the DFI system to communicate diagnostic information
– Engine parts include magneto rotors with different inertias and a 12-tooth output sprocket
– Optional chassis parts include handlebar holder for a 1 1/8-inch handlebar, 46
– to 50-tooth aluminum and steel rear sprockets, solid petal brake rotors, different fork and shock springs and manual decompression lever and cable
Key Kawasaki KX 250F Technology
Factory Tuning, FI to Keep Expert Riders at the Front of the Pack
The KX250F base package provides an excellent platform for race-experienced riders to win races in the top classes. Design of the highly rigid aluminum frame, suspension components and settings focused on ensuring control is maintained during high-speed riding – especially in straight lines – to enable experienced racers to ride full out. And to deliver holeshot-winning performance – a key factor that can mean the difference between running up front and winning, or getting stuck mid-pack – chassis geometry and the high-revving 4-stroke engine’s wide powerband were designed to maximise rear wheel traction. The combination is a proven race-winner, with multiple AMA Supercross Lites and Motocross Lites championships to its credit.
To ensure the Lime Green racers continue to run at the front, Kawasaki engineers made a number of engine and chassis changes to further increase the KX250F’s winning potential.
More powerful, fuel-injected engine with factory tuning
– specs on par with our factory racers
– Tuned to best suit race-experienced riders, the 249 cc liquid-cooled, 4-stroke Single’s wide powerband focuses on high-rpm performance and extends way into the over-rev.
– quick throttle response
– superb over-rev characteristics
– Tuned for high performance, the wide powerband extends way into the over-rev. A works-base bridged-box bottom piston (used for the first time on a mass-production motocrosser on the 10MY KX250F) is just one of many features inspired by our factory racers.
– NEW To ensure the high-rpm engine’s demand for a high flow of gas in a short period is met, the KX250F’s injector features larger holes than that used on the KX450F. A fine atomising injector with 4 holes disperses spray particles with a droplet size of 120µm. Fuel flow is about 20% greater than on the KX450F.
– NEW stronger low-mid torque allows riders to corner a gear higher (less shifting)
– NEW KX FI Calibration Kit (option) identical to that used by our factory teams
– NEW exhaust revisions to meet stricter noise regulations
High-speed chassis with factory-style components and tuning
– NEW Showa’s Separate Function front Fork (SFF)
– Left fork tube: damping assembly
– Right fork tube: spring
– With only one spring, the friction generated between the spring(s) and fork inner tube(s) is greatly reduced (approximately 25% less)
– Removing the damper assembly from the right fork tube frees up space for a preload adjuster.
– racer friendly: suspension jobs are quicker & easier
– improved left/right balance
– NEW chassis fine-tuning for revised rigidity balance results in increased lateral chassis flex
– lighter turning
– increased rear wheel traction
– more planted feel from front wheel
– enhanced cornering accuracy
– control maintained during high-speed riding (in straights and when cornering)
– NEW aggressive graphics
– blacked-out rims
– NEW Fork and rear shock adjusters have a blue alumite1 finish
NEW 249 cc liquid-cooled, 4-stroke Single with fuel injection
Tuned to best suit race-experienced riders, the 249 cc liquid-cooled, 4-stroke Single’s wide powerband focuses on high-rpm performance and extends way into the over-rev.
Tuned for high performance, the wide powerband extends way into the over-rev. A works-base bridged-box bottom piston (used for the first time on a mass-production motocrosser on the 10MY KX250F) is just one of many features inspired by our factory racers.
NEW Progressive throttle link
A 43 mm throttle body makes use of a progressive throttle link to deliver airflow in much the same way as would a FCR carburettor. Using two linked shafts, the throttle body opens more quickly after the 3/8 open position, delivering sharp response and excellent power feeling.
NEW Setting-adjustable motocross ECU
The KX FI Calibration Kit contains KX Racing software, an ECU controller, mounting brackets and damper, harness and USB cable. In addition to the kit, a PC and 12 V battery are all that is required.
NEW Less mis-shifts
Shift mechanism revisions offer more accurate shifting.
NEW Reduced noise
Changes to silencer internals ensure that stricter noise regulations are met.
All-aluminum perimeter frame
Slim aluminum perimeter frame is a lightweight construction composed of forged, extruded and cast parts.
NEW Lighter-handling chassis
Increased chassis flex, revised rigidity balance and reduced fork offset result in lighter turning, increased rear wheel traction, a more planted feel from the front wheel and enhanced cornering accuracy.
New Uni-Trak rear suspension
Linkage mounts below the swingarm for more precise suspension tuning.
NEW Separate Function front Fork (SFF)
Showa’s Separate Function front Fork (SFF)
NEW Rear shock absorber
Rear shock damping settings, revised to match the new SFF, offer improved action and increased absorption performance.
A factory-style Renthal (standard-type) aluminum handlebar is standard equipment.
Slim rider interface
Bodywork components and seat designed to offer a slim, natural riding position making it easier for racers to go fast.
Revised pattern for the seat sides offers more grip.
Petal brake discs
Among the KX250F’s numerous factory-style components are its front and rear petal disc brakes.
NEW Factory styling
Fork and rear shock adjusters
View all images…
Powerful, High-Revving Fuel-Injected Engine with Factory-Style Tuning
Tuned to best suit race-experienced riders, the 249 cc liquid-cooled, 4-stroke Single’s wide powerband focuses on high-rpm performance and extends way into the over-rev. Already featuring race-inspired tuning and parts like the high-performance piston with bridged-box bottom (a mass-production first when introduced on the 2010 KX250F), the 2011 engine receives fuel injection and a number of changes for even more power, stronger low-mid range torque (most noticeable when riding through the whoops, landing jumps and coming out of tight turns, it allows riders to shift less often, reducing fatigue and enabling quicker lap times), more accurate shifting and a quieter exhaust note.
Factory-racer engine tuning
– High-performance piston, featuring the same design used on our factory racers, contributes to improved performance at all rpm, A short skirt, reinforced external ribs and the industry’s only mass-production use of a bridged-box bottom, featuring fully flush internal bracing, result in a lighter, stronger piston.
NEW – A new piston crown, revised to suit chamfering of the squish area, offers increased high-rpm and over-rev performance.
NEW – Intake camshaft with revised sprocket/shaft arrangement retards intake valve timing 1o, to suit the new fuel-injected engine.
Open 41o BTDC 40o BTDC
Close 71o ABDC 72o ABDC
Valve lift was also increased (8.7 mm >> 9.3 mm) and, accordingly, stronger valve springs were used.
NEW – A new spark plug protrudes 1.4 mm deeper into the combustion chamber, improving combustion efficiency.
NEW – Intake ducting has about 10% greater volume, resulting in improved response (especially in the ultra-low rpm range).
NEW – The revised intake ducting and new deep-protrusion spark plug not only offset the drop in low-mid torque that comes from a change to fuel injection, performance is actually improved in this range.
NEW – Revised final reduction ratio offers improved engine feel. The shorter gearing (13/48T >> 13/50T) further accentuates the increased low-end torque.
NEW – Cylinder height reduced (36.5 mm >> 36.3 mm) to suit the new piston and higher compression ratio: now 13.5:1 (previously 13.2:1).
NEW – Exhaust pipe is longer (480 mm >> 510 mm) to suit new engine characteristics.
Battery-less fuel injection system
Designed specifically for motocrossers, the fuel injection system incorporates a small lightweight ECU and operates without a battery to further eliminate unnecessary weight. And of course, fuel injection eliminates the need to adjust engine settings to suit track and climate conditions.
NEW – Ensuring quick starting without a battery was a prime directive when developing this fuel injection system. Using only electricity generated by the kick starter, the engine can be started with only three rotations of the crankshaft. The system delivers electricity in the following order: 1) ECU, 2) fuel pump, 3) injector. With a warm engine, starting can be accomplished in a single kick.
NEW – The compact, lightweight ECU, located just in front of the steering head (behind the number plate), was designed specifically for motocross use. To help cope with the shocks and vibrations of motocross riding, the fuel pump relay is built in to the ECU.
NEW – A 43 mm throttle body makes use of a progressive throttle link to deliver airflow in much the same way as would a FCR carburettor. Using two linked shafts, the throttle body opens more quickly after the 3/8 open position, delivering sharp response and excellent power feeling.
NEW – Lightweight throttle body is approximately half the weight of a FCR carburettor – a weight savings of about 600 g.
NEW – To ensure the high-rpm engine’s demand for a high flow of gas in a short period is met, the KX250F’s injector features larger holes than that used on the KX450F. A fine atomising injector with 4 holes disperses spray particles with a droplet size of 120µm. Fuel flow is about 20% greater than on the KX450F.
NEW – The newly designed fuel pump, located in the fuel tank, is a lightweight aluminum construction. (Fuel tank capacity is now 7.2 litres.)
NEW – To ensure a stable fuel supply during vigorous motocross riding the fuel pump features a rubber fuel filter cover that wraps around the inlet port and acts as a fuel trap. A fuel return hose from the pressure regulator ensures there is always fuel in the fuel trap.
Factory KX FI Calibration Kit (optional part # 99999-0289)
The KX FI Calibration Kit is the same kit used by Kawasaki’s works teams in Europe and the U.S. The kit enables expert riders to adjust engine characteristics (by rewriting actual data maps) to suit their preference, record riding data, and analyze their riding data to further fine-tune their settings.
NEW – The KX FI Calibration Kit contains KX Racing software, an ECU controller, mounting brackets and damper, harness and USB cable. In addition to the kit, a PC and 12 V battery are all that is required.
NEW – While the kit is designed to satisfy racers and expert riders, it is simple and hassle-free to use:
– the ECU controller mounts behind the number plate for easy access
– accessing the ECU is accomplished simply by connecting to a PC via the ECU controller using a USB cable (no additional switches are necessary)
– setting adjustments can be prepared in advance on a PC, or done when connected to the ECU
– the kit’s user-interface is simple to understand and easy to use
NEW – The KX FI Calibration Kit contains seven preset settings that can be quickly and easily used to adjust the ECU to suit track conditions. The provided settings are shown below.
Richer fuel setting fuelling 5% richer than stock
Leaner fuel setting fuelling 5% leaner than stock
Advanced ignition setting ignition advanced 3° from stock
Retarded ignition setting ignition retarded 3° from stock
Hard riding surface setting ignition retarded, fuelling richer
Soft riding surface setting ignition retarded, fuelling richer
Beginner setting engine power suppressed:
ignition retarded, fuelling richer
NEW – For more advanced setting optimisation, the ECU maps for volume of fuel injected (via the FI adjustment window) and ignition timing (via the IG adjustment window) can be adjusted for given throttle position and rpm.
– Base settings are shown as a flat graph. Settings can be increased or decreased from the base according to rider preference.
NEW – Multiple display options are available. Click [3D Graph] or [2D Graph] of the [3D/2D] to select the 3 or 2-dimensional display. When you use the [3D Graph], select [Surface Display] or [Frame Display] of the [3D Graph Type] to select the display type.
NEW – Both click-and-drag (using the graph window) and numerical editing (using the map sheet) are possible.
NEW – When connected to the ECU, the KX FI Calibration Kit can be used to display the status of a running engine. Information can be displayed in numeric form using the Data Monitor , or in visual form using the various display options offered by the Data Meter.
NEW – The KX FI Calibration Kit can also be used as a data logger, recording up to six hours of data depending on the number of parameters (engine rpm, angle of throttle opening, etc) being recorded. After riding, the riding data can be viewed using the [Analyze] window . Parameters to be recorded and displayed can be selected independently.
NEW – The logged data can lined up with the course layout to check actual riding, enabling more efficient FI settings to be determined. It also enables before-and-after comparisons and comparisons between riders.
For more detailed information on use and functions of the FI Calibration Kit, please refer to the KX FI Calibration Kit Instruction Manual.
NEW – A longer ratchet lever causes the ratchet to turn a greater amount with each shift (53° >> 60°), reducing the chance of mis-shift.
NEW – A lighter ratchet lever return spring ensures that shift lever weight feel remains the same.
NEW – On North American models, revised internal construction results in a quieter silencer that clears stricter 94 dB noise regulations.
Additional performance-oriented engine characteristics
– The engine was tuned such 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 forward momentum.)
– Efforts were made to achieve the widest possible torque band, so that traction efficiency would be maximised for a greater part of the rev range.
– Lightweight titanium valves (IN: 31 mm; EX: 25 mm) reduce reciprocating weight and offer high-rpm reliability. The ultra-light valves have extremely thin valve stems on par with those found in supersport machines. The intake valves feature thicker heads for increased strength and both intake and exhaust valves are formed from a highly rigid, titanium material.
– Crank web design increases offsetting moment for a high crankshaft balance factor. At close to 60%, the balance factor of the ’11 KX250F is on par with our factory racers. The high balance factor contributes to reduced engine vibration, smoother power delivery and increased performance in the mid-high rpm range.
– 32 mm thick, 117.8 mm wide radiators with wide fin and tube pitch offer resistance to mud build-up while maintain cooling performance. The radiators are strong enough that the reinforcing brackets could be eliminated, resulting in lower overall weight.
– Sprocket-style chain drive roller helps smooth engine braking by reducing the effect of driveline lash when the rider gets off the gas quickly and play in the lower side of the chain suddenly tightens. The additional control facilitates corner entry.
High-Speed Chassis with Factory-Style Components and Tuning
The KX250F’s slim aluminum perimeter frame is a lightweight construction composed of forged, extruded and cast parts. Chassis balance and settings were all set to suit race-experienced riders. The centre of gravity and key dimensions (swingarm pivot, output sprocket and rear axle locations) were chosen so that the rear tyre would drive the bike forward (instead of causing it to squat). For ’11 the high-speed chassis benefits from a new Separate Function front Fork (SFF) with greatly reduced friction that offers increased riding comfort and improved suspension performance. In addition to enhanced handling offered by the SFF’s improved left/right balance, increased chassis flex and revised frame rigidity balance offer lighter handling and increased turning performance. The highly acclaimed high-speed stability of its predecessor remains unchanged.
While the frame remains essentially the same as that of the 10MY model, revised rigidity balance results in a frame with moderate lateral flex.
NEW – Frame’s front and side hangers (engine mounting brackets), previously aluminum, are now formed from steel, and are thinner (front: t6.0 mm >> t4.5 mm; side: t8.0 mm >> t4.5 mm).
NEW – The resultant increased lateral chassis flex enables lighter turning.
NEW – The revised rigidity balance offers a number of benefits:
– increased rear wheel traction
– more planted feel from the front wheel
– enhanced cornering accuracy makes it easier for riders to follow the line they want
NEW – Reduced fork offset (23.5 mm >> 22.5 mm) also contributes to the lighter handling, enhanced cornering accuracy and more planted feel of the front wheel. Additionally, it also gives the bike a more compact feel.
Superior rear-wheel traction
– The New Uni-Trak rear suspension system mounts the suspension arm below the swingarm, allowing a longer rear suspension stroke. The longer stroke in turn allows more precise rear suspension tuning.
– Extensive rider testing was conducted to determine the ideal linkage ratios and rear shock absorber damping settings to achieve maximum rear wheel traction.
Race-oriented suspension: Separate Function front Fork
Showa’s Separate Function front Fork (SFF) makes its first appearance on a mass-production motocrosser. The SFF separates damping and shock absorption duties:
– Left fork tube: damping assembly
– Right fork tube: spring
The configuration offers both smooth action and firm damping performance – a combination difficult to achieve with a conventional fork.
NEW – With only one spring, the friction generated between the spring(s) and fork inner tube(s) is greatly reduced (approximately 25% less) , resulting in extremely smooth action throughout the fork stroke.
NEW – Being able to use a larger damper piston not only enables smoother action, it also makes firm damping performance possible.
NEW – Removing the damper assembly from the right fork tube frees up space for a preload adjuster. Having a preload adjuster greater simplifies the task of setting fork preload or front height. (With a conventional fork, only the rear could be adjusted easily; adjusting the front required fork tubes to be disassembled and the use of collars and special tools. With SFF, both the front and rear preload/height can be set quickly and easily.)
NEW – In addition to preload adjustment, the racer-friendly SFF also facilitates other maintenance chores like adjusting damping and changing springs.
MAINTENANCE JOB STD SFF
Adjust preload: Collars needed Y Adjust via dial
Adjust preload: Remove & disassemble Y –
Adjust preload: Special tools Y –
Adjust damping: Places 4 2
Change spring rate: Remove fork x2 –
Change spring rate: Disassemble x2 x1
Change spring rate: Special tools Y –
Change spring rate: Number of springs 2 1
NEW – SFF offers improved left/right balance, which greatly enhances handling. Locating the heavy spring in the right tube (and fine-tuning the left and right tube strength) better offsets the previously unbalanced weight of the brake caliper and disc on the left side.
NEW – A restrictor added on the damper assembly side and a joint rod comp added on the spring side ensure that natural character is maintained. Placement of the restrictor can be used to change damping characteristics; it contributes to idealised damping character. The joint rod comp ensures even left/right damping force and contributes to ideal fork rigidity.
– A super-hard titanium coating on the outer surface of the inner fork tubes reduces sliding friction (and stiction) and improves action, contributing to the smoother ride. The increased surface hardness of the dark navy blue coating also helps to prevent scratches and damage to the tubes. (The KX250F is the only motocrosser in its class to feature this race-ready coating standard.)
– Friction-reducing Kashima Coat on the inside of the fork outer tubes contributes to smoother suspension action (especially at the initial part of the stroke) and a better ride feel.
Race-oriented rear suspension
NEW – Rear shock damping settings, revised to match the new SFF, offer improved action and increased absorption performance.
– The rear shock features dual compression adjustability, allowing high-speed and low-speed damping to be tuned separately.
– The rear shock also features the Kashima Coat on the tank cylinder. The reduced friction smoothes suspension action.
Factory-style and other race-oriented components
– Among the KX250F’s numerous factory-style components are its front and rear petal disc brakes. In addition to helping reduce unsprung weight, the wave shapes of the petal discs help clean the brake pads for more efficient braking performance.
– Rear caliper guard protects the caliper from damage.
– A factory-style Renthal (standard-type) aluminum handlebar is standard equipment.
– Rib-less rear hub and butted spokes reduced unsprung weight.
– Rims are coated in black alumite1 – just like our factory racers.
NEW – Fork and rear shock adjusters have a blue alumite1 finish like our US factory racers.
– Factory-style graphics complement the KX250F’s highly tuned performance.
Designed with rider ergonomics in mind, bodywork components offer the rider a slim interface, the natural position making it even easier for racers to go fast.
– Formed using a double-injection moulding process, 2-tone shrouds contribute to the slim package.
– 2-tone side covers are also formed using a double-injection moulding process. Like the shrouds they contribute to the slim package. A hole in the right-side cover helps cool the silencer.
– The frame widens at the ankles to offer the rider better grip and narrows near the bend below the seat to allow a slim riding position.
– The seat uses a slip-resistant top surface for good grip when seated and smooth sides for excellent rider mobility.
NEW – Revised pattern for the seat sides offer more grip than before.
– Seat urethane designed to keep the original shape longer.
– Wide (front-to-rear) footpegs designed to offer grip and superb feel at the pegs.
– The clutch cable boot features a large quick adjuster, making it easier for riders to adjust play in the clutch cable.
– Throttle grip has a unitised collar. The one-piece unit provides additional stability during throttle operation.
– Lightweight short-length grips feature a pattern designed to provide excellent grip.
– Electrofusion treatment on cylinder bore results in a surface with good oil retention. Further, the molybdenum on the surface of the cylinder bore helps resist scorching, contributing to durability.
– The alloy swingarm uses a cast front section, tapered hydroformed spars and forged chain adjusters.
NEW – Swingarm is longer to accommodate the larger rear sprocket, and is now common with the KX450F. The chain is also longer: 112 links >> 114 links.
– Large synthetic skid plate offers great protection with minimum weight.
NEW – Front chain guide (chain slider) uses a thicker plastic lining, offering longer wear life.
– Optional engine parts include magneto rotors with different inertias (8.5, 9.5 kgÃ¸cm2; STD: 9.0 kgÃ¸cm2) and a 12T output sprocket (STD: 13T).
– Optional chassis parts include handlebar holder for a f28.6 mm bar (STD: f22.2 mm), aluminum and steel rear sprockets (48-52T; STD: 50T), solid petal brake rotors for wet races, and different springs for the front fork (8.7, 9.1, 9.5 N/mm; STD: 9.1 N/mm) and rear shock (47, 48.1, 49, 50, 51, 52, 53, 53.9 N/mm, STD: 51 N/mm).
NEW – An FI indicator lamp (optional part # 23016-0049) warns of any problem with the FI system.
Colours- Lime Green with new factory-style graphics
2011 Kawasaki KX 250F – USA Specifications
Engine: Four-stroke single with DOHC and four valves
Bore x stroke: 77.0 x 53.6mm
Cooling System: Liquid
Fuel injection: 43mm Keihin throttle body
Compression ratio: 13.5: 1
Ignition: Digital DC-CDI
Transmission: Five-speed with wet multi-disc manual clutch
Final drive: Chain
Frame Type: Aluminum perimeter
Rake/Trail: 28.2 degrees / 4.7 in.
Front suspension / wheel travel: 47mm inverted Showa SFF telescopic fork with spring preload adjustability and 22 position compression and 20 position rebound damping adjustability/ 12.4 in.
Rear suspension / wheel travel: Uni-Trak® linkage system and Showa shock with 19 position low-speed and stepless high-speed compression damping, 22 position rebound damping and fully adjustable spring preload / 12.2 in.
Front Tire Size: 80/100-21
Rear Tire Size: 100/90-19
Front brakes: Single semi-floating 250mm petal disc with dual piston caliper
Rear Brakes: Single 240mm petal disc with single-piston caliper
Overall length: 85.4 in.
Overall width: 32.3 in.
Overall height: 50.0 in.
Wheelbase: 58.1 in.
Ground Clearance: 13.0 in.
Seat height: 37.2 in.
Curb weight: 232.7 lbs.
Fuel capacity: 1.9 gal.
Color Choices: Lime Green
2011 Kawasaki KX 250F – Canada Specifications
MSRP: $TBA CDN
Type Liquid-cooled, 4-stroke Single
Displacement 249 cc
Bore and Stroke 77.0 x 53.6 mm
Compression Ratio 13.2:1
Valve System DOHC, 4 valves
Fuel System Fuel Injection: Ã¸ 43 mm x 1 (Keihin)
Ignition Digital DC-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 1.750 (28/16)
3rd 1.444 (26/18)
4th 1.235 (21/17)
5th 1.045 (23/22)
Final Reduction Ratio 3.846 (50/13)
Clutch Wet multi-disc, manual
Type Perimeter, aluminum
Wheel Travel: Front 315 mm
Wheel Travel: Rear 310 mm
Tire: Front 80/100-21 51M
Tire: Rear 100/90-19 57M
Caster (Rake) 28.2°
Trail 120.2 mm
Steering Angle (left/right) 42° / 42°
Front: Type 47 mm upside-down telescopic Separate Function front Fork (SFF)
Compression Damping 22-way
Rebound Damping 20-way
Spring Preload 60-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
Front: Type Single semi-floating 250 mm petal disc
Rear: Type Single 240 mm petal disc
Overall Length 2,170 mm (85.4 in.)
Overall Width 820 mm (32.3 in.)
Overall Height 1,270 mm (50 in.)
Wheelbase 1,475 mm (58.1 in.)
Ground Clearance 330 mm (13 in.)
Seat Height 945 mm (37.2 in.)
Curb Mass 105.6 kg (232.8 lbs.)
Fuel Capacity 7.2 litres (1.6 gal.)
Colour Lime Green
* The Manufacturer’s Suggested Retail Price does not include freight, pre-delivery inspection or applicable taxes. The final price is at the discretion of the dealer. Prices and Specifications are subject to change without prior notice.
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. Available colours may vary by market.