Many new improvements for the motocrosser with 17 AMA 125cc championships in last 19 years
Completely redesigned for 2004 and ridden to victory in the 2003 125 Western Region Supercross Series by Team Chevy Trucks Kawasaki factory racer James Stewart, the Kawasaki KX125 returns to the lineup with significant refinements to make this championship-winning race bike even more potent for 2004.
In the eternal quest for power in the highly competitive 125 class, 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 PowerValve 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 newlink 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 UNITRAK 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 04.
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.
All KX motorcycles come with the support of Team Green¿, Kawasaki’s amateur support program. Team Green’s regional support vehicles and highly trained technicians provide technical information and assistance for anyone who rides or races a Kawasaki. Team Green also offers a comprehensive contingency program for amateur and professional riders who place well at designated events.
Information about the KX125 motorcycle and Kawasaki’s complete line of family recreational products can be found on the Internet at www.kawasaki.com. Accessories for KX motocross bikes can also be purchased online at www.buykawasaki.com.
Kawasaki Motors Corp., U.S.A., (KMC) markets and sells at wholesale Kawasaki motorcycles, ATVs, JET SKI® watercraft, MULE¿ utility vehicles, power products and small engines. Kawasaki’s tagline, Let the good times roll¿, is recognized worldwide for the spirit of fun, adventure and high performance that characterizes the Kawasaki recreational vehicle line. Kawasaki product lines are sold through a network of more than 1,500 independent retailers. The company and its affiliates employ nearly 2,400 people in the United States, with approximately 550 of them located at the Irvine, California headquarters.
2004 KAWASAKI KX125
Features and Benefits:
Refinements to the liquid-cooled, two-stroke engine result in improved power. These include:
- Reshaped combustion chamber
- Higher compression ratio
- Piston ring locating pin moved to rear of piston to evenly distribute ring pressure at front of piston
- Improved KIPS design provides better seal to piston
- Reshaped expansion chamber provides more power and is recessed from rider’s leg
- Two-stage reed valve increases low-end flexibility, prevents over-flexing at high rpm
- New carburetor settings
- Straightened air duct and carburetor holder
- Revised ignition
- Increased clearance between connection rod big-end and nylon crankcase “stuffer,” increasing lubrication
- New connecting rod made of stronger steel
- Left crankcase casting is more rigid, clutch cable-to-case now sealed with an O-ring
- Stronger radiator side brackets help prevent deformation
- Engine bolts made of stronger steel
- Stronger exhaust silencer mounting brackets and stronger igniter bracket
Chassis and Suspension
- New UNI-TRAK® rear suspension link is anchored on the swingarm, drastically reducing front-to-back movement of the shock, resulting in smoother, more stable action and improving traction at the rear wheel when accelerating
- Forged, one-piece actuating rod for UNI-TRAK replaces two-piece extrusions
- Frame construction is lighter due to suspension loads being absorbed by the new 20mm longer swingarm
- Upper cross tubes and engine mounts are modified to idealize stiffness balance for enhanced cornering performance and improved durability
- New semi-sealed cartridge fork provides better damping and fork action
- More compact front axle brackets feature new clamping method
- Adjustable rubber handlebar mounts help reduce vibration
- Flatter seat improves riding position and raises seat height 8mm
- Textured slip-resistant seat cover helps keep rider in place
- Foot pegs raised 3mm to suit the improved riding position
- Rear brake pedal pivot is mounted 11.5mm higher for increased ground clearance
- Fuel tank uses oblong mounting hole for easier maintenance
Kawasaki Options (Available Through Kawasaki Dealers)
- Flywheel rotors allow riders to alter the amount of engine inertia to suit riding style and track conditions
- 20-inch front wheel for various track requirements
- Different front and rear sprockets
- Solid brake disc for muddy race conditions
- Softer and stiffer fork and shock springs
2004 KX125 SPECIFICATIONS*
|Engine||Two-stroke single cylinder with KIPS®|
|Bore x stroke||54.0 x 54.5mm|
|Induction||6-petal carbon fiber crankcase reed valve|
|Frame||Perimeter style, high-tensile steel with aluminum subframe|
|Rake/trail||27.5° / 3.9 in.|
||Two-stroke single cylinder with KIPS®
||Bore x stroke
||54.0 x 54.5mm
||6-petal carbon fiber crankcase reed valve
||Perimeter style, high-tensile steel with aluminum subframe
||27.5° / 3.9 in.
||Suspension type, front
||Kayaba 48mm inverted telescopic
||Suspension adjustments, front
||16-way preload and rebound damping
||Suspension type, rear
||UNI-TRAK® swingarm, single shock
||Suspension adjustments, rear
||Spring preload, 16-way compression and rebound
||Wheel travel, front
||Wheel travel, rear
||Brakes, front / rear
||Kawasaki Lime Green
*Specifications subject to change
lvetica, sans-serif”>Suspension type, front
*Specifications subject to change