Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/128331
What Kawa§aki 5ay§... What"§ New and Why KX250 ($5999) Engine • Head gasket changed from metal gasket to O -rings for improved sealing and more accurate deck height • New intake design features a single po rt w ith mo dified le ngt h and angle for improved intake effi ciency • Scavenging port ex it angle is changed for improved scavenging efficiency, and the crankcase mating area around the scavenge ports has been increased. Third scaveng ing port also modified for improved flow • New reed-valve angle, air guide and reed block are cha nged for improved throttle respo nse • Intake air duct is reshaped to suit revised intake manifold • New ex pansion chamber dimen sions and improve d constructio n (change d from fou r-piece to three -p iece) co ntribute to improved engine pe rformance • Redesigned pisto n uses new rings and new pisto n sealing grooves to prevent ring snagging; stronger pin boss improves durability • Clutch release shaft and lever modified, and re lease mechanism moved behind generator cover • Shift performance improved by using involute splines on the fifth gear and on the output shaft. A needle bearing added to the shift shaft imp roves shift feel • Ne w water pump uses new pump gear ratios and a new impellor for increased coolant circulation, plus a new water jacket arou nd the exhaust po rt eliminat es t he nee d for an external coola nt ho se • Sprocket cover, governor cover, inner/outer clut ch covers, and water pump cover changed to suit new crankcases • Generator cover changed from plastic to magnes ium fo r improved appearance and increased functionality • Revised carb uretor settings co ntribute to imp roved throttl e respo nse, and a new car b holder allows straighter incoming airflow • Radiator core len gth increased (from 220 to 240mm) for improved cooling per formance • Upg raded ignition system feature s KXI25 KX250F ($5599) increased cond enser capacity and a gen erator w ith a built-in regulator for lighter weight . Stato r shape changed, and new wiring harness use d. Ignition timing changed to suit new power characte ristics • New, short er spark plug eases maintenance and weighs less • New, lightweigh t ignition coil is more com pact • Ignition coil primary terminals feature waterproof couplers for increased reliability Low-fric tion throttle barrel also reduces throttle operating friction Rider Controls • Stainless thr ottle cable wire wit h a greater numbe r of thinner strands delivers superb, low -friction throttle operatio n • Clutch cable o uter liner changed fro m polyethylene to Teflon for red uced friction • Clutch adjuster added to clutch lever perch • New front brake lever has better feel Chassi s/Suspension • Steering rake reduced to 26 degrees to quicken stee ring response • Foo tpegs are wide r and offer better grip; shorter transverse lengt h means greater cornering clearance • Wider handlebar mounts (increased from 90 to 98mm) help prevent handle bar bending • New lightweight 0 .1.0 fron t rims with lightweight spo kes and nipples red uce unsprung weight • New cross-section for rear rims also designed for lighte r weight • lig ht fo rk and shock mounting bolts and a new rear brake master cylinder w ith a unit ized reservoir and sho rter yoke (I 7.Smm shorter than '04 KX250) con tribute to light weight • Fork mounting bolt location s changed on the to p triple clamp for easier mainte nance and str o nger mou nting • New front brake pad material offers better feel and perfo rma nce • Chain guide roller now uses two bearings for greate r dura bility • Rear subframe has larger forged upper mounting brackets for improved durability • Fuel tank filler o utlet is increased from 37 to 46mm for easier fueling Engine • St raighter exhaus t port and extended ribs in both the intake and exhaust ports improve low to midrange respo nse • Throttle bar rel utilizes new low-fr iction de sign for improved rider co nt rol and pe rfo rmance feedback • Revised ignition system timing improves to p-end and over-rev pe rformance • Rev-limiter changed to spark drop out co ntro l for smooth power drop -off and excellent over-rev characteristics Radiators are 40 mm longer for improved cooling efficiency • Water pump cover and oil filter cap are now se parate for simplified mainte nance . • Muffler features new packing and co nstructi o n for longer se rvice and increased durability Transmission • Third and fourth input gears are shotpeened for improved reliability and durability • New clutch friction plates have fewer contact pads to pro vide the ride r with a mo re direct clutch fee l • Clutc h springs are made fro m new, more durable material to resist sagging • Clutch adjuste r makes adjustments o n the trac k quick and easy • Clutch cable outer liner now made of Teflon for smoo ther clutch action Chass is • Head pipe wa ll t hickness has bee n increased from 2.6 to 3.2m m for improved handling • Footp egs are wider and offer better grip • Chain guide roller now uses tw o bearings for greater durability Front Suspension • Kayaba semisealed, 48mm inverted cartridge forks have new low-friction seals for smoother action through the stroke range • Fo rk mou nting bolts have been reloca ted on the top triple clamp for easier mainte nance and stronger mou nting • lig hter fork and rear shock moun ting bolts contribute to red uced overall weight • Widt h of handlebar mo unts have been increased from 90 to 98mm to help prevent bending Brakes • Dual-pisto n 250mm front disc brake uses new pad material for improve d per- KXIOO KX85 www.cydenews.com forman ce and rider fee l • Ne w front brake lever provides ride r w ith better feed back Bodywork • New seat cover uses high-grip top for good grip whe n co rnering and smoothe r sides for trans it ioning from sitti ng to sta nding • More durable uret hane foam improves com fort and durability KX 125 ($5099) Engine • Fuel co llection cham ber added to the pilo t jet for improved th ro tt le response w he n accelerating from a closed throttle • Redesigned reed valve air guide and ho lde r help prevent heat-in d uced defo rmatio n • Two-stage re ed valve design increases , low -end flexibility prevents over- flexing at high rp m • Stainless thrott le ca ble w ire with greater number of thinner stran ds delivers superb, low -friction throttle res ponse • Clutch , chain and generator covers features an attractive new grey stone color Chassis and Suspension • UNI-TRAK® rear suspension link is anchored on the swingarm, drastically reduci ng fro nt-to-back movement of the shock , resulting in smo other, more stable act ion and improvin g traction at t he rear whee l w hen accelerating • Sw ingarm has increased spar wa ll thickness for enhanced stab ility and hand ling • Uppe r cross tubes and engine mounts are modified to idealize stiffness balance fo r enhanced cornering performance and improved durab ili y t • New, low-friction fork seals provide smoother actio n throughout the stroke • lighter fork and rear shock mounting bolts cont ribute to redu ced weigh t • Softe r compound tires and new tread design offer better tractio n fo r med ium to hard t racks • Ne w seat has high-grip top for good grip w hen cor neri ng and smooth sides fo r transitio ning from sitting to sta nding • Durable ure tha ne seat foam improves comfort and wear KX65 CYCLE NEWS . JULY 7, 2004