Kawasaki KX 250 (1990-1991): A Timeless Motocross Contender Revisited
Introduction
The early '90s marked a golden era for two-stroke motocross machines, and the Kawasaki KX 250 (1990-1991) stands as a defining icon of this period. Designed to dominate rough tracks and outmuscle competitors, this green beast combined raw power with surprisingly nimble handling. Even by modern standards, its legacy persists among vintage MX enthusiasts and weekend warriors seeking unfiltered riding excitement. Let’s throttle through what makes this generation of KX 250 unforgettable.
Design & First Impressions
The KX 250’s aggressive stance screams purpose. Its angular plastics, high-mounted fenders, and minimalist bodywork reflect the no-nonsense ethos of early '90s motocross design. At 96.5 kg (212.7 lbs), the bike feels shockingly light when you throw a leg over it – a trait that becomes even more apparent on the track. The slim fuel tank (8.5L / 2.25 gal) keeps the center of gravity low, while the 385 mm (15.2") ground clearance hints at its appetite for jumps and whoops.
The cockpit is straightforward: analog instrumentation is nonexistent (this is a pure race machine), and the crossbar handlebar gives a commanding view of the front wheel. Build quality feels robust, with Kawasaki’s trademark green frame components resisting flex under hard riding.
Engine Performance: Two-Stroke Fury
Fire up the kickstarter, and the 249cc liquid-cooled two-stroke roars to life with a raspy, adrenaline-inducing bark. The 52.5 HP (38.3 kW) peak power arrives at 8,000 RPM, but it’s the torque curve that impresses most – 47.5 Nm (35 ft-lbs) at 7,500 RPM delivers a violent mid-range punch that launches you out of corners.
The Keihin carburetor provides crisp throttle response, though it demands precise jetting for optimal performance. Below 5,000 RPM, the engine feels docile, but once the power valve opens, acceleration becomes explosive. Riders must stay active – clutch work is essential to keep the revs in the sweet spot. Compared to modern four-strokes, the power delivery is less linear but far more theatrical.
Handling & Suspension: A Dance Partner for Rough Terrain
Kawasaki’s chassis geometry strikes a balance between stability and agility. The 26.5° rake and 113 mm (4.4") trail provide sharp steering without headshake at speed. Inverted front forks (310 mm / 12.2" travel) soak up square-edged bumps better than conventional forks of the era, while the rear monoshock (330 mm / 13" travel) maintains traction even when landing hard off jumps.
On tight tracks, the KX 250 feels telepathic. The narrow 815 mm (32.1") width lets you thread through ruts, and the 1480 mm (58.3") wheelbase inspires confidence in high-speed sections. Braking is handled by single discs front and rear – adequate for the era but requiring deliberate lever pressure compared to modern setups.
Competition: How the KX 250 Stacked Up
The early '90s 250cc motocross class was fiercely competitive. Here’s how the KX 250 fared against its rivals:
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Honda CR250R (1990-1991): Honda’s chassis was slightly more refined, with a reputation for cornering precision. However, the KX’s engine had a stronger mid-range hit, making it preferred for riders who relied on power over finesse.
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Yamaha YZ250 (1990-1991): Yamaha’s rear suspension linkage provided better bump absorption, but the KX countered with a lighter feel (YZ250 weighed 103 kg vs. KX’s 96.5 kg) and quicker revving engine.
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Suzuki RM250 (1990-1991): The RM250 was often dubbed the “cornering king” for its sharp handling, but its peaky powerband demanded expert-level throttle control. The KX offered a more forgiving torque curve for intermediate riders.
While all four Japanese manufacturers had strong offerings, the KX 250 carved its niche as the “rider’s bike” – less polished than the CR250R but more thrilling for those willing to tame its wild side.
Maintenance: Keeping the Green Beast Alive
Owning a 30-year-old motocross weapon requires vigilance. Here are key maintenance considerations:
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Engine Rebuilds: Two-strokes live hard. Piston replacements every 30-40 hours are mandatory. MOTOPARTS.store offers aftermarket forged pistons for improved durability over OEM.
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Cooling System: The liquid-cooled design was advanced for its time but demands regular coolant flushes. Inspect hoses for dry rot – our silicone hose kits are a worthwhile upgrade.
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Carburetor Tuning: Swap stock jets for modern Keihin alternatives to handle ethanol-blended fuels. Pair with a high-flow air filter (available in our store) to unlock smoother throttle response.
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Suspension Refresh: Rebuild fork seals annually and consider upgrading rear shock oil to synthetic blends. We stock OEM-spec seal kits and performance fluids.
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Brake Upgrades: Replace worn discs with wave-style rotors for better bite, and pair with organic brake pads to reduce fade during long motos.
The Riding Experience: Raw, Rewarding, and Unapologetic
Riding the KX 250 is a sensory overload. The vibrations from the single-cylinder engine travel through the handlebars, the exhaust note crackles on deceleration, and the seat barely cushions landings – but that’s the point. This bike doesn’t coddle; it demands respect.
On hardpack tracks, the Dunlop Geomax-style tires (front: 80/100-21, rear: 110/90-19) provide predictable slide control. In deep sand or mud, swap to knobbier treads from our tire selection. The lack of electric start feels archaic, but the kickstarter rarely requires more than two prods when properly tuned.
Legacy & Modern Relevance
Three decades later, the 1990-1991 KX 250 remains a favorite for vintage MX racing. Its simplicity makes it easy to repair, and the aftermarket support (including our extensive parts catalog) ensures it can be kept race-ready indefinitely. While modern bikes offer EFI and launch control, the KX delivers something they can’t – pure, unbridled two-stroke exhilaration.
Conclusion: A Classic Worth Reviving
The Kawasaki KX 250 (1990-1991) isn’t just a relic; it’s a living testament to an era when motocross bikes were less computerized and more visceral. Whether you’re restoring one for vintage races or want a weekend project that’ll terrify your neighbors, this KX delivers. And when it’s time to rebuild, upgrade, or personalize, MOTOPARTS.store has every gasket, sprocket, and performance mod you’ll need to keep the green machine alive.
Got a KX 250 project? Explore our curated selection of Kawasaki KX 250 parts to make your ride faster, tougher, and uniquely yours.
Specifications sheet
| Engine | |
|---|---|
| Stroke: | Two-stroke |
| Starter: | Kick |
| Ignition: | CDI |
| Max power: | 38 kW | 51.0 hp |
| Max torque: | 48 Nm |
| Fuel system: | Carburettor |
| Max power @: | 8000 rpm |
| Displacement: | 249 ccm |
| Max torque @: | 7500 rpm |
| Bore x stroke: | 67.4 x 70.0 mm (2.7 x 2.8 in) |
| Configuration: | Single |
| Cooling system: | Liquid |
| Number of cylinders: | 1 |
| Dimensions | |
|---|---|
| Wheelbase: | 1480 mm (58.3 in) |
| Dry weight: | 97 |
| Overall width: | 815 mm (32.1 in) |
| Overall height: | 1215 mm (47.8 in) |
| Overall length: | 2177 mm (85.7 in) |
| Ground clearance: | 385 mm (15.2 in) |
| Fuel tank capacity: | 8.5 L (2.25 US gal) |
| Drivetrain | |
|---|---|
| Final drive: | chain |
| Transmission: | 5-speed |
