Cycle News - Archive Issues - 1980's

~ 00 O"l (Above) The KX500 is all new for '86: It has new styling, one spark plug and weighs 220.5 pounds. (Below) The KX260 now has a power-valve. (Above) The KX126, like the 260, has a new power valve and revised suspension. ~ther.feature~ include a new intake system (below left) and a carburetor slide WIth a radIUS cut-away around the nHelle jet. Gone on all models is the front fender stabilizer. /- Fresh Air Intake System (F .A.I.S.l New rides for '85: Kawasaki By Kit Palmer Heading the 1985 motocross line-up from Kawsaki is the all-n~w KX500, 'completely redesigned with a 499cc water-cooled engine with dual aluminum radiators and 57.2 bhp. Compression ratio has been increased from 7:1 to 7.9:1; bore and stroke is 86 x 86mm. Also new is the VM40 R-Slide car- 14 buretor and suction resonator (boost bottle) on the KX500 and 250. The carb features a flat-bottom slide with a radi used cutaway around the needle to improve low-speed atomization and air £low. This is supposed to enhance low-end and mid-range power, while the larger venturi Mikuni (up from 38mm) is designed for more power on top. The suction resonator (boost bottle) - positioned between the carb and reed block - reduces intake turbulence resulting in better throttle response. On all the KXs, Kawasaki has a new Fresh Air Intake System (FAIS) that delivers cleaner and unrestricted air to the engine through the front number plate grill, a special airbox ~nder the fuel tank, and ducts directly lOto the standard airbox behind the carbo Because of detonation problems in 1983, '84 KX500 came with a dualplug head to help eliminate the problem; however, for '85 the KX has just one spark pi ug, positioned in the center of the head. Along with the redesigned pipe, the new aluminum silencer is rebuildable. The kickstarter and shiftlever are aluminum to reduce weight: The £ram~ is all new and is made of lighter high-tensile steel. The Uni-Track rear suspension on the KX500, 250 and 125 are significantly updated. New is a dual-range compression damping system that comprises of two four-way external adjusters: one controlling damping rates in low-speed situations, and one controlling damping rates in highspeed situations. When the shock is loaded slowly, the low-speed damping control keeps the rear wheel from hopping; when the shock is loaded quickly, the high-speed damping control helps prevent bottoming. The preload and. rebound damping adJusters rematn unchanged. The shock on the 500, 125 and 250 also has an automatic heat compensator to reduce damper fade. As the temperature of the shock increases with heavy use and the oil expands, a spring-loaded, tampered-needle valve progressively increases effective damping to help maintain constant performance. The Last change made to the rear suspension is the addition of an adjustable vertical strut, which allows the rider to set ride height within a 30mm range. Rear axle travel has been increased to 12.8 inches. Like last year'smodel, the forks on the 500,250 and 125 have eight-way compression damping, but they now have three-way preload settings. Fork stanchion tubes are 43mm. Although the front disc brake diameter has increased by 20mm,the weight has been reduced by drilling holes in the disc. The rear brake is unchanged. The diameter of the front axle has been increased by 2mm, while the diameter of the rear axle has been increased by 3mm on the 125,250 and 500. The KX500 weighs 220.5 Ibs. dry. Like the KX500, the 250 features all-new plastic design: radiator shrouds, tank, side panels and fenders are reshaped. Both the KXI25 and 250 now incorporate the Kawasaki Integrated Power-valve System (K.I.P.S.). This system is designed to give better low-end and top-end power output without losing mid-range power. Major K.I.P.S. components include an exhaust resonator, two auxiliary exhaust sub-ports, two valves that open and close the resonator and sub-ports, and a crankshaftdriven ball-ramp governor. At low rpm, the dual valves simultaneously open the resonator and close the subports. At high rpm, the valves close the resonator and open the sub-ports to boost top-end power. The linkage between the governor and valves has only two moving parts and is wellprotected to help eliminate reliability problems. The 250 also has a new center-port exhaust design, modified stator and a new ignition curve. It also has the VM4QR-Slide Mikuni carburetor and air guide at the reed valve. The twin radiators are redesigned: They're longer and narrower and are mounted outside the downtubes of the double-cradle frame. To lower the overall center of gravity, the radia- tors are mounted 2.2 inches lower, and to improve cooling efficiency, the cylinder and cylinder head have been modified. Actual displacement is 249cc and the bore and stroke is 70.0 x 64.9mm. Compression ratio is 9. I: I. The KX 125 looks very similar to last year's, but the new 125 features many of the same modifications as do the 250 and 500 KXs. Its motor now has the K.I.P.S., lighter chassis, threeway preload adj ustroent on the fork, updated Uni-Trak suspension and redesigned exhaust pipe. The 125 has a VM34 R-Slidecarburetor with ovalbore venturi. It still has a 124cc displacement and has a 56.0 x 50.6mm bore and stroke. Compression ratio is 9.35: I. Gone is the front fender stabilizer on all bikes. The minicyde champ of '84, the KX80 still looks very similar to the '84 model, but it does have many changes. It has a new exhaust pipe and thicker reed valves. Intake and exhaust port profiles are modified and the piston profile is also changed. There is now a separate shaft for the water pump to prevent crank damage, and one friction and one driven plate are added to the clutch. The aluminum swingarm is allnew: It is a box-section type with slide-type chain adjusters and has been lengthened half-an-inch, which increases wheelbase. The shock has four-way compression damping settings, while the fork tubes are shortened below the axle to increase ground clearance. A grease nipple is added to the Uni-Trak linkage. Brake shoe material is new to eliminate excessive drum wear. The airbox cover is redesigned for easier maintenance, and the radiator shroud and guard are new. • KX600 Engine type Uquid-cooled. two-stroke alngle Bore x stroke. . . . . . .. 88x88mm Dispillcement 499cc Compression retlo. _ 9.9:1 Carburetlon VM40 Mlkunl

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