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For this version of Basic Metal, we’re going to have a look again at Kawasaki’s all-new KX250 for 2005.
With the two-stroke 250’s period of dominance rapidly drawing to an in depth, Kawasaki threw one final main replace on the legendary KX250 in 2005. Picture Credit score: Kawasaki
The early 2000s have been a little bit of a tough patch for Kawasaki’s venerable KX250. After dominating the shootout standings for a number of years within the late Nineteen Nineties, the inexperienced machines took a significant step again within the first years of the brand new century. Obese, underpowered, and outsized, the KX250s of the early 2000s have been reasonably disappointing machines.
By far essentially the most important replace made to the KX250 in 2005 was the introduction of its all-new 249cc motor. Redesigned from the bottom up, the brand new mill featured a extra vertical cylinder placement to shorten the consumption tract, prolong the exhaust port, and allowed for using bigger cooling jackets in crucial areas. Picture Credit score: Kawasaki
In 2003, Kawasaki set about righting their 250 fortunes with an all-new 250 machine. The redesigned KX featured an all-new chassis that improved dealing with, decreased weight, and improved ergonomics. The brand new machine ditched the Paul Bunyan really feel the KX had loved for over a decade in favor of a way more compact structure that felt extra in line with the tastes of contemporary racers. Slim, trim, and with significantly better dealing with, the brand new KX was a significant enchancment in each class however one. Sadly, that one class was energy, and right here the KX proved a significant letdown. Porting, energy valve and ignition adjustments did little or no to spice up the facility output of a motor that would hint its roots again to the primary Clinton administration. Nice, torquey, and responsive, the KX’s motor was nice off-road, however simply lower than going toe-to-toe with the 250 class prime weapons on a motocross circuit.
An all-new body for 2005 maintained the fundamental structure of 2004 however repositioned the shock mounting, decreased the width of the principle spars, and rebalanced the flex traits of the chassis to enhance dealing with and really feel. Picture Credit score: Kawasaki
For 2004, Kawasaki dialed up one other slew of Band-aid fixes for its geriatric motor however none of them did a lot to enhance its firepower on the observe. At its peak, it gave up over three horsepower to its rivals and was no match for the broad output of the YZ or prompt snap of the RM. Novices and off-road riders loved its mellow supply, however hard-core motocross racers lamented its lack of hit and non-existent top-end efficiency.
All-new pegs for 2005 have been wider and positioned greater on the chassis for higher consolation. A brand new swingarm was added that featured elevated stiffness to stop flex within the tough. This was paired with a redesigned Uni-Trak linkage that supplied a revised curve for smoother motion. Picture Credit score: Kawasaki
For 2005, Kawasaki knew that they would wish to step up their motor sport to have any hope of holding the KX on the buying lists of any severe racers. The transfer to four-strokes was completely underway and the 2004 KX250 had bother operating with different two-strokes and no hope of holding powerhouses just like the YZ450F in sight. With that in thoughts, Kawasaki threw the complete drive of their R & D division on the 2005 KX.
James Stewart’s transfer to the 250 class in 2005 was one of the crucial hyped within the sport’s historical past. His exploits on the 125 had many questioning if a brand new period of inexperienced domination was about to be unleashed on the premier division. Whereas his velocity was by no means in query, Stewart’s inconsistency and propensity for crashing would sidetrack a lot of his rookie season. Picture Credit score: Motocross Motion
First up was an entire redesign of the KX’s engine. The brand new energy plant didn’t share a single half with the ’04 design except for its 38mm Keihin Powerjet carburetor. The brand new motor featured the identical 64.4 x 72.0mm bore and stroke and 249cc of displacement because the ’04, however every thing else was new. The redesigned cylinder was moved to a extra vertical place to permit for an extended exhaust port and bigger water jackets. The brand new top-end featured O-rings for the top gasket to enhance sealing and reconfigured porting for improved top-end efficiency. The piston was new and integrated particular grooves to stop ring snagging. The KIPS (Kawasaki Built-in Energy-valve System) was redesigned and featured a two-stage valve that allowed the principle and sub-valves to work independently for a smoother supply. An all-new consumption moved the carburetor nearer to the cylinder for elevated circulation and a redesigned reed valve was added for improved throttle response. A reshaped enlargement chamber was bolted on and tuned for extra top-end energy. The Keihin PWK38S Powerjet carburetor remained and was built-in with an all-new ignition that offered higher condenser capability and a lighter-weight generator. New jetting specs have been added to the carburetor to work with the redesigned energy plant and an upgraded throttle cable was put in that supplied higher stretch resistance and a smoother really feel.
Secure at velocity however barely imprecise within the turns, the KX was far more snug railing the skin line than making an attempt to dive to the within in 2005. Right here off-road hero Destry Abbot demonstrates the KX’s high-speed cornering talents for Dust Bike journal. Picture Credit score: Dust Bike
The second most vital replace for the KX250 in 2005 was the transfer to Kayaba’s all-new Air Oil Separation System (AOSS) fork. Related in idea to Showa’s profitable Twin Chamber design, the AOSS promised smother operation and extra constant damping by separating the air and oil chambers of the forks to stop aeration of the fluid. Picture Credit score: Kawasaki
The underside finish of the KX motor was simply as new and featured redesigned circumstances that supplied a narrower profile than in 2004. A brand new crank was put in with a 2mm enhance in crank internet diameter for improved gasoline charging. Engine cooling was improved by way of using an all-new water pump with a revised impeller and new radiators that featured a 20mm enhance in core thickness. Contained in the transmission, there was a brand new fifth gear and a redesigned output shaft that includes involute splines for an improved shifting really feel. Needle bearings have been additionally added to the shift shaft for smoother efficiency. A brand new clutch mechanism repositioned the pivot level to contained in the ignition cowl and a brand new Teflon coating was added to the cable to enhance the texture. To assist comfort, an “on the fly” adjuster was integrated into the perch to permit for mid-moto changes.
All-new clamps for 2005 positioned the bar mounts farther aside to stop twisting in a crash. The mounts may be reversed to extend room for taller pilots. Whereas the clamps have been cutting-edge, the inventory metal bars the KX got here fitted with most actually weren’t. Picture Credit score: Kawasaki
By way of outward look, the 2005 KX250 appeared similar to the 2004 mannequin, however the two machines shared little or no except for their styling. All-new in 2003, the KX’s bodywork carried over largely unchanged except for a minor replace in graphics, a 10mm taller seat (with gripper cowl), and an enlarged filler gap for the gasoline tank. Apart from that, the 2005 KX appeared like a close to clone of the 2004 mannequin.
Except for its retreaded bodywork, the KX250 was nearly all-new in 2005. Picture Credit score: Kawasaki
In reality, nonetheless, the 2005 KX250 chassis featured an extended record of adjustments aimed toward enhancing efficiency. First up was an all-new body that retained the metal perimeter development Kawasaki had employed since 1990. This design offered a robust and flex-free basis for the chassis however had typically been criticized for its girthy really feel. In 2005, Kawasaki appeared to handle this by trimming the midsection of the machine and narrowing the width of the body on the footpegs. The brand new body featured a one-degree discount in rake and a repositioning of the rear suspension mounting factors to enhance dealing with response. The brand new Uni-Trak employed a stronger swingarm for 2005 and a revised linkage aimed toward lowering flex and enhancing monitoring within the tough. Whereas the swingarm was stronger, different components of the body have been decreased in stiffness in an try to attain the optimum “stiffness stability.” By repositioning the flex factors of the chassis Kawasaki hoped to offer the chassis a extra responsive really feel with out sacrificing power and stability.
In supercross, the all-new KX250 gave 250 rookie sensation James Stewart the facility he wanted to run on the entrance. Picture Credit score: Simon Cudby
To scale back the prospect of a rider catching their ft in ruts, each the brake pedal and footpeg mounts have been repositioned greater on the body and the pegs themselves have been widened for an elevated chew and improved consolation. New triple clamps have been put in that moved the reversible bar mounts farther aside by 8mm for 2005. This was carried out to stop the mounts from twisting within the occasion of a crash. Whereas the bars remained metal in development, a brand new bend was added to raised work with the upper pegs and reshaped saddle for 2005. New light-weight rims and spokes shaved off a couple of ounces whereas beefed-up subframe mounts improved sturdiness.
An all-new seat for 2005 featured a narrower profile, elevated peak, stiffer foam, and a non-slip cowl for elevated rider consolation. Picture Credit score: Kawasaki
On the suspension entrance, the KX250 was all-new up entrance and reasonably revamped within the rear. New forks for 2005 upgraded the suspension efficiency by shifting to Kayaba’s new Air Oil Separation System (AOSS) that separated the air and oil chambers to stop frothing of the fluid. Related in idea to Showa’s Twin-Chamber design, the AOSS fork supplied improved damping, decreased fade, and a discount in stiction by way of using particular low-friction seals. For 2005, these 48mm inverted models supplied 11.8 inches of wheel journey with 16 exterior changes out there for compression and rebound damping.
After a number of years of mild-mannered KX250s, the inexperienced crew got here roaring again with a significant powerhouse in 2005. The brand new motor pumped out 4 extra horsepower than the 2004 and delivered a brutal midrange hit that blasted the KX out of each nook Whereas not as simple to handle because the 2004, most severe racers discovered the brand new mid-and-up motor preferable to the friendlier however less-thrilling older design. Picture Credit score: Kawasaki
Within the rear, the Uni-Trak rear suspension featured a brand new ratio for the linkage and a beefed-up swingarm as its most vital updates. The Kayaba shock remained largely unchanged from 2004 with new damping settings to match the revised linkage curve being essentially the most noteworthy replace. Just like the forks, the KYB damper supplied 16 exterior changes for compression and rebound damping. As in 2004, it lacked the high-low velocity compression adjuster of earlier KXs and lots of of its rivals.
With all that energy on faucet and an explosive supply, the 2005 KX250 might be an actual handful in slippery circumstances. Picture Credit score: Steve Bruhn
On the observe, the KX250 was an entire new animal in 2005. The redesigned motor was head-and-shoulders higher than in 2004 and completely within the operating for the very best two-stroke 250 motor of the 12 months. On the dyno, it pumped out 4 extra horsepower than the 12 months earlier than and did so with a way more aggressive supply. In ‘04, the KX had supplied a clean and mellow supply that inexperienced persons and off-road guys cherished however moto heads discovered missing. For 2005, that was not a priority with the redesigned motor delivering a barking and snarling fashion of energy that blasted out of turns and despatched rooster tails flying. The brand new energy plant gave up a superb little bit of low-end grunt to the older KX however made up for it with an explosive mid-range hit and blistering top-end pull. As soon as on the pipe, the KX was an absolute rocket and able to hanging with something within the class. With its gentle low-end and abrupt midrange, the KX might be a handful if traction was restricted, nonetheless. On exhausting and slick surfaces, the inexperienced machine tended to gentle up the rear tire, and right here the smoother and torquier YZ250 had a bonus. As with earlier KX250s, the clutch and transmission lacked a number of the finesse of its rivals and this compounded the issue in transferring the Kawasaki’s prodigious energy to the bottom. Shifting remained barely notchy and the clutch’s engagement continued to be grabby regardless of the brand new cable and mechanism. It was a motor that longed for traction and rewarded aggression but additionally penalized these with out the ability to harness its potential.
Indoors, the KX250 was greater than able to operating with its 250 rivals, however open air, the transfer to 450 four-strokes left Stewart and the inexperienced crew at a definite drawback. Picture Credit score: Very important MX
Within the hierarchy of 2005 250 two-stroke powerbands, the brand new KX250 match someplace proper between the lighting quick RM and broad YZ. It was considerably quicker than the Honda, more durable to trip than the Yamaha, and virtually as fast because the Suzuki. This made it by far essentially the most aggressive Kawasaki 250 energy package deal in half a decade and eventually a match for its rivals. With the four-stokes overtaking the category, that aggressive benchmark was rapidly shifting, however in the interim, the KX was a powerband contender.
At 226 kilos, the KX250 was the heftiest of all of the 250 two-strokes and solely 5 kilos shy of Honda’s in style CRF450R. Whereas the facility traits and decrease reciprocating mass of the two-stroke made that distinction really feel bigger, there was no denying the truth that the KX was not as feathery feeling as its 250 competitors. Picture Credit score: Dust Bike
On the dealing with entrance, the KX supplied a middle-of-the-road dealing with package deal that skewed towards stability reasonably than corner-shredding nimbleness. The brand new body didn’t change the KX’s persona and the machine remained the identical massive and long-feeling bike it had been for greater than a decade. Tall riders loved this roomy structure, however smaller riders commented on the heftier really feel the KX imparted. This sense was borne out on the size with the KX clocking in at a comparatively portly 226 kilos. That was 13 kilos heavier than the light-weight KTM and solely 5 kilos shy of Honda’s CRF450R four-stroke. Whereas this gave the KX a planted and stable really feel at velocity, it did hinder its nimbleness within the tighter sections of the observe. Right here, the KX felt noticeably much less keen to be thrown round than featherweights like Honda’s 218-pound CR250R. The brand new steeper geometry did little to dispel the KX’s imprecise really feel at turn-in and lots of riders discovered the Kawasaki to be unpredictable within the turns. Typically it oversteered, and generally it understeered with the entrance wheel trying to find a chew. A few of this most likely needed to do with the chassis’ stability which was skewed too closely towards the entrance. With the inventory linkage in place, the rear of the machine was jacked to the moon giving it a really “entrance heavy” really feel. The quickest repair for this was an aftermarket hyperlink that lowered the rear of the bike and balanced out the chassis. This improved turning however the KX remained much less exact than its rivals at searching the within line.
The KX’s new forks supplied a major enchancment in trip consolation over the “semi sealed cartridge” fork employed in 2004. The brand new AOSS design supplied a clean and compliant trip that devoured up braking bumps and made small chatter disappear. Bottoming was a difficulty for actually quick guys, however most riders cherished the texture of the brand new entrance finish. Picture Credit score: Kawasaki
Whereas the inventory KX was not notably nice within the turns, it was admirably steady at velocity. There was not one of the hyperactive really feel the Suzuki exhibited and a KX usually adopted its meant path with little drama. Headshake was minimal and the KX might be trusted to trace straight and true by way of most high-speed sections.
By far the most important criticism most riders had with the KX in 2005 was its inventory chassis stability. The mix of the brand new linkage and gentle entrance forks gave the bike a robust ahead bias that performed havoc with its dealing with really feel. Stiffer entrance springs and an aftermarket hyperlink have been the quickest fixes to even out the KX and get the very best efficiency out of its chassis. Picture Credit score: Kawasaki
A few of that high-speed confidence was actually as a result of KX’s wonderful suspension which offered a clean and compliant trip on the observe. The brand new AOSS fork supplied little or no stiction and offered an excellent really feel on small bumps and chatter. Total settings have been barely softer than the very related fork discovered on the Yamaha YZ250, and this helped contribute to the KX’s front-heavy bias. Some quicker riders additionally complained of bottoming on massive jumps and a wierd “clunk” sound which might be heard when maxing out their journey. Fortunately, nonetheless, the bottoming system did a superb job of isolating the rider from any harsh jolts on the bars. Whoops, bumps and reasonably sized jumps have been all taken in stride and the forks usually did an excellent job of going about their enterprise. Greater and quicker riders wanted stiffer settings however for almost all of riders, they have been wonderful performers in inventory situation.
In inventory situation the rear suspension on the 2005 KX250 was a stable performer. The general really feel was firmer than in 2004 and it took most large hits with nary a whimper. Picture Credit score: Kawasaki
Out again, the KX’s new suspension offered a barely firmer really feel than the earlier KX250. Whereas firmer than in 2004, it remained softer general than a lot of its rivals. This translated to an opulent really feel on most obstacles and a clean trip within the tough. With the inventory linkage in place, there was the occasional kick below acceleration, however the aftermarket hyperlink that balanced out the chassis additionally alleviated a lot of this by altering the leverage ratio to stop the shock from dropping to date down into its stroke below energy. Even with the inventory hyperlink in place, nonetheless, it was an opulent and principally well-sorted rear finish.
Total dealing with was much less exact than most of its rivals however the KX had greater than sufficient thrust to energy its means out of tight turns in 2005. Picture Credit score: Motocross Motion
On the detailing entrance, the KX remained a mixture of appreciated enhancements and head-scratching disappointments in 2005. On the thumbs-up record have been new brakes which supplied a major enchancment in really feel, Teflon-coated cables for smoother motion, sano pipe coating, bigger gasoline filler, upgraded bar mounts, taller and stiffer seat foam, non-slip seat cowl, and a three-pound discount in weight. Within the thumbs-down class have been the KX’s old-school metal bars, a bizarre behavior of portray their swingarms black after which silver, grabby clutch, notchy shifting, and nonetheless disappointing weight. Many riders included the KX’s stale appears on this class as effectively, feeling such a major improve in efficiency warranted not less than a light replace in appears. No less than the bike was good-looking, except for its skyward-pointing rear finish.
Lastly quick, the KX250 supplied an aggressive package deal in want of a bit of fine-tuning in 2005. Picture Credit score: Kawasaki
Total, the 2005 Kawasaki KX250 turned out to be a major enchancment in almost each class of motocross efficiency. With its blazing quick motor, the KX lastly had the firepower to tackle its 250 rivals, nevertheless it did demand extra ability to get that energy to the bottom. The brand new forks, improved ergonomics, upgraded brakes, and reinvigorated energy plant turned an also-ran into an prompt contender. The jacked-up rear, cranky transmission, massive really feel, and demanding energy held it again from being a unanimous selection for the highest 250 within the land, however for these with the ability to harness its potential, the 2005 KX250 was an especially efficient motocross weapon.
On your every day dose of basic moto, you’ll be able to comply with me @tonyblazier on Twitter and Instagram.
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