2004 KAWASAKI KX125
Kawasaki engineers succeeded in boosting overall power of the 2004 KX125 and revised the chassis for even sharper handling characteristics.
*The combustion chamber of the liquid-cooled, 124cc, two-stroke single-cylinder engine is reshaped and compression increased to give it more low and mid-range power and crisper throttle response.
*Aiding the enhanced throttle response is a new piston and ring, which has the piston ring locating pin at the rear of the cylinder to evenly distribute the ring pressure at the front of the piston for better reliability.
*Plus, an improved Kawasaki Integrated Power Valve System (KIPS) design reduces the gap between the valves and piston when the valves are fully closed, giving the KX125 more lower rpm power. KIPS varies the exhaust port height to broaden the useful rpm range for good low-end and mid-range without sacrificing top end power.
*Other power-enhancing changes include a redesigned expansion chamber shaped for increased midrange and top-end power.
*The weave direction of the carbon fiber reeds introduced last year have been rotated to a 45-degree angle, increasing the flexibility of the reeds to improve low- and mid-range torque characteristics.
*To prevent over-flexing at high rpm, a second layer of smaller reeds reinforce the main reeds. The result is the best of both worlds: highly responsive low- and mid-range, plus performance of stiffer reeds at high rpm.
*The Mikuni TMX38x carburetor features new settings, and the intake manifold and air duct are straighter for increased air flow and enhanced response at the lowest rpm levels. *The ignition has also been revised, further boosting performance and improving reliability of the engine by reducing irregular combustion.
*A new crankshaft with increased clearance between the connecting rod big-end and nylon crankcase “stuffer” offers better lubrication of the big-end bearing, and the new connecting rod is made of stronger steel.
*The new casting for the left crankcase is more rigid and has improved clutch cable-to-case sealing using a new O-ring.
*The six-speed transmission from the previous model is utilized, and a stronger chain guard of more durable material is also fitted for 2004.
*Mirroring the chassis of the all-new KX250F, the most significant change to the KX125 is the new link Uni-trak rear suspension system. Unlike previous KX models in which the Uni-trak link was anchored to the frame, the link on the new system is anchored on the swingarm. This drastically reduces front-to-back movement of the Kayaba shock as the suspension is compressed, resulting in smoother suspension action and significantly improved traction, especially while accelerating.
*The revamped Uni-trak rear suspension provides 12.2 inches of travel with 16-way compression and rebound settings.
*The frame’s thickness and shape of the upper cross tubes and engine mounts are modified to idealize chassis stiffness for enhanced cornering performance and improved durability.
*A new Kayaba 48mm inverted, semi-sealed cartridge fork with 11.8 inches of travel handles front suspension duties for the KX125 and features 16-way compression and rebound settings.
*The front wheel is also modified with more compact axle brackets and a new clamping method.
*The front fork guards are also restyled for 2004.
*The front brake line is now routed directly to the single-disc brake caliper rather than under the bottom of the fork leg as on the previous model, resulting in a slightly lighter brake hose, improved brake feel and much easier maintenance.
*To improve rider position and enhance cornering, seat height has been raised 8mm in the middle for a flatter profile and the seat itself features a new textured slip-resistant cover.
*To suit the new riding position, the footpegs are 3mm higher and the rear brake pedal pivot is mounted 11.5mm higher. *Other durability improvements include a new radiator with stronger side mounting brackets that help to prevent deformation by the rider’s knees and by other impacts.
*The fuel tank now utilizes an oblong mounting hole for easier maintenance.
*The subframe also benefits from a strong silencer mounting bracket and new engine mounting bolts are made of stronger material so they can be torqued more tightly.
2004 KAWASAKI KX250
The 2004 KX250 has received a host of refinements resulting in increased engine performance, improved handling and greater rider comfort.
*To give the 249cc two-stroke engine excellent top-end without sacrificing hard-hitting low- to midrange power, the combustion chamber has been reshaped for higher compression, the intake ports have been reshaped, and the new crankcase casting eliminates the boost port at the rear of the cylinder to speed the fuel-air mixture through the transfer ports.
*Plus, a one-piece aluminum KIPS valve replaces the earlier two-piece steel valve, the KIPS governor ball guide has been reshaped, and new expansion chamber dimensions all contribute to improved power delivery.
*Other improvements include new carburetor settings that provide crisper response at partial throttle, reshaped air duct and intake manifold for straighter airflow.
*New ignition timing and ignition rotor also contribute to improved power across the entire rpm range.
*To further enhance throttle response, the crankcase “stuffers” mounted to the crank webs have been changed from aluminum to nylon and lead inertia weights have been eliminated.
*Piston durability has been improved by “streaking” the skirt with fine oil-retaining grooves and by tin-plating the piston.
*The most significant change to the KX250 chassis is the new-link Uni-Trak rear suspension system.
*Unlike previous KX models in which the Uni-trak link was anchored to the frame, the link on the new system is anchored on the swingarm. This drastically reduces front-to-back movement of the Kayaba shock as the suspension is compressed, resulting in smoother suspension action and significantly improved traction, especially while accelerating.
*The revamped Uni-trak rear suspension provides 12.2 inches of travel enhanced by 16-way compression and rebound settings.
*Also, the thickness and shapes of the upper cross tubes and engine mounts have been modified to idealize the stiffness balance for enhanced cornering performance and improved durability.
*A new Kayaba 48mm, works-type semi-sealed cartridge inverted fork with 11.8 inches of travel handles front suspension duties for the KX250 and features 16-way compression and rebound settings.
*Other modifications include more compact axle brackets with a new clamping method.
*The front brake line is now routed directly to the single-disc brake caliper rather than under the bottom of the fork leg as on the previous model, resulting in a slightly lighter brake hose, producing improved brake feel and simplifying maintenance.
*Other changes include restyled fork guards and a stronger chain guard of more durable material.
*Seat height has been raised 8mm in the middle for a flatter profile and the seat itself features a new textured slip resistant cover.
*Plus, the fuel tank uses an oblong mounting hole for easier maintenance.
2004 KAWASAKI KX250F FOUR-STROKE
The KX250F is powered by a 249cc, liquid-cooled, four-stroke, single-cylinder engine featuring double overhead cams and four valves. With an over-square bore and stroke of 77.0 x 53.6mm to help ensure high revs, it features a forged piston, chrome composite plated aluminum cylinder, titanium valves, billet camshafts and alloy steel tappets. The engine’s “semi-dry” oil sump contributes to a low center of gravity. Oil is routed internally through the cylinder’s bolt passageways, eliminating the weight and complexity of external oil lines and increasing the engine’s durability.
*To help keep the KX250F as light as possible, several engine components are made from lightweight materials, including magnesium generator, outer clutch and cylinder head covers, titanium exhaust headpipe and aluminum silencer.
*The KX250F is designed to start easily, whether hot or cold, due to its Kawasaki Automatic Compression Release (KACR) system and hot start circuit. KACR slightly opens one exhaust valve while the engine is being kick started to ease compression.
*The Keihin FCR37 flat-slide carburetor, which is operated by a push-pull throttle, is also equipped with hot start circuit. If the KX250F is tipped over or stalled, the rider pulls a small lever that is unitized with the clutch lever, drawing extra air into the carburetor to give it a leaner, faster-burning fuel mixture, making starting easier.
*Ignition is provided by a digital AC-CDI system featuring a dual ignition map and rev limiter. When the transmission is in neutral, the ignition allows for a low idling speed. When the transmission is in gear, the second ignition map is used, increasing idle rpm for reduced engine-braking effect.
*The new engine is matched to a quick-shifting, five-speed transmission.
*The transmission uses a ratchet shift mechanism for light shifting action, and clutch components are the same as those used on the KX125.
*The KX250F frame has new D-section tubes on the upper frame rails, enabling the slim bodywork to “hug” the frame more tightly. Plus, frame width has been narrowed 40mm at the footpegs. Combined with a steeper rake angle and foot pegs that are placed higher and closer together in the frame, the slimmer profile improves rider position on the bike for enhanced cornering performance.
*A new Kayaba semi-sealed, 48mm inverted cartridge fork with 11.8 inches of travel handles front suspension duties for the KX250F and features 16-way compression and rebound damping settings.
*On the rear, a revamped Uni-trak rear suspension provides 12.2 inches of travel with 16-way compression and rebound damping settings. Unlike previous KX models in which the Uni-trak link was anchored to the frame, the link on the new system is anchored on the swingarm. This drastically reduces front-to-back movement of the Kayaba shock as the suspension is compressed, resulting in smoother suspension action and significantly improved traction, especially while accelerating.
*Stopping power is provided by a dual-piston 250mm front disc brake. The brake hose is made of a single layer of Kevlar and is routed directly to the front caliper, improving brake feel and reducing weight.
*The 240mm rear brake features a more compact caliper to ensure adequate clearance for the muffler when the suspension is fully compressed, and the brake pedal is forged for high strength and light weight.
*The KX250F is fitted with lightweight wheels and mounted with 80/100-21 Bridgestone M51 front and 100/90-19 M57 rear tires.
*A 20-inch front wheel is also available as an option through Kawasaki dealers.
*Restyled bodywork distinguishes the KX250F from its two-stroke cousins, including a longer rear fender, side covers that are more oblong in shape and sharply angled radiator shrouds that give the bike an aggressive, “streamlined” stance. Plus, the seat is flatter than on previous KX models and features a textured slip-resistant cover.
*In addition to redesigned fork guards, the KX250F also features an aluminum skid plate and plastic side guards to protect the engine.
*Because the KX250F engine is more fuel efficient, the fuel tank has a 2.0-gallon capacity, providing additional weight savings.