KTM 250 SX (2007–2010): A Two-Stroke Legend for the Dirt Devotee

Introduction

The KTM 250 SX, produced between 2007 and 2010, remains a benchmark for two-stroke off-road performance. Designed for riders who crave raw power, agility, and a visceral connection to the trail, this Austrian machine carved its reputation as a no-compromise competition bike. While modern four-strokes dominate headlines, the 250 SX’s snarling two-stroke engine and race-ready geometry keep it relevant even today. After spending hours thrashing this orange beast through rocky trails and motocross tracks, it’s clear why this generation is still sought after by riders who value simplicity, adrenaline, and that unmistakable two-stroke scream.

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Engine and Performance: The Heart of a Predator

At the core of the KTM 250 SX lies a 249cc liquid-cooled two-stroke engine, a design that prioritizes explosive power delivery over refinement. The Keihin PWK 36S AG carburetor ensures crisp throttle response, while the Kokusan ignition system delivers reliable spark even in punishing conditions. With a bore and stroke of 66.4 mm x 72 mm (2.6 x 2.8 inches), this engine is tuned for mid-to-high RPM aggression, rewarding riders who aren’t afraid to wring its neck.

Key Takeaways:
- Powerband Personality: The 250 SX doesn’t do “gentle.” Crack the throttle, and the engine surges forward with a ferocious hit that demands respect. Unlike modern four-strokes, there’s no torque cushion at low RPM—this bike lives in the upper half of the rev range.
- Gearbox & Clutch: The 5-speed gearbox pairs perfectly with the hydraulic wet multi-disc clutch, offering buttery-smooth shifts even under load. Riders will appreciate the clutch’s minimal lever effort during technical sections.
- Weight Advantage: At 95.4 kg (210 lbs) dry, the 250 SX feels like a feather compared to its four-stroke rivals. This translates to effortless flickability in tight corners and mid-air adjustments on jumps.

The Two-Stroke Experience: Forget fuel injection or electric starters—this bike is all about analog thrills. The ritual of mixing fuel (1:60 oil ratio) and the satisfying kick of the starter connect you to a purer era of motorcycling. The aluminum exhaust system amplifies the engine’s raspy bark, a soundtrack that’s equal parts thrilling and nostalgic.

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Chassis and Handling: Precision Meets Brutality

The KTM 250 SX’s central double-cradle chromoly steel frame strikes a balance between rigidity and flex, providing confidence at high speeds while absorbing trail chatter. Paired with WP suspension components, this bike handles like a precision tool—sharp, predictable, and brutally effective.

Suspension Breakdown:
- Front: The WP USD 48 mm fork offers 300 mm (11.8 inches) of travel, adjustable for compression and rebound. It’s stiff enough for hard landings but compliant over roots and rocks.
- Rear: The WP PDS (Progressive Damping System) shock delivers 335 mm (13.2 inches) of wheel travel. The PDS design eliminates linkage, reducing weight and simplifying maintenance—a boon for racers.

Handling Notes:
- With a 26.5° rake and 1475 mm (58.1 inches) wheelbase, the 250 SX turns with surgical precision. It carves ruts like a BMX bike and remains stable at speed.
- Ground clearance of 385 mm (15.2 inches) lets you glide over obstacles without hesitation.
- Brakes: The single 220 mm discs front and rear lack the bite of modern setups but offer progressive feel—ideal for slippery off-road conditions.

Tires & Wheels:
- Front: 80/100-21 – A proven size for tackling everything from sand to hardpack.
- Rear: 110/90-19 – Provides ample traction for aggressive corner exits.

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Ergonomics and Comfort: Built for Attack

The KTM 250 SX’s cockpit is minimalist and aggressive. The 985 mm (38.8-inch) seat height (varies slightly by year) positions riders in a commanding stance, ideal for standing attacks on technical terrain. Narrow bodywork allows easy weight shifting, while the grippy seat foam keeps you anchored during hard acceleration.

Fuel & Range:
The 7.5–8.0-liter (1.98–2.11 US gal) tank is adequate for 1.5–2 hours of racing, though trail riders might crave more capacity. Pro tip: Carry a spare fuel bottle for longer adventures.

Standout Feature:
The orange-and-black color scheme is iconic. Even after a muddy ride, the bike looks ready for a photoshoot—a small but satisfying detail for proud owners.

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Competition: How the 250 SX Stacks Up

1. Yamaha YZ250 (2007–2010)

• Pros: Softer power delivery, legendary reliability.
• Cons: Heavier (103 kg/227 lbs), less adjustable suspension.
• KTM Edge: Lighter weight, hydraulic clutch, sharper handling.

2. Honda CR250R (2007)

• Pros: Smooth powerband, refined chassis.
• Cons: Discontinued after 2007; parts scarcity.
• KTM Edge: Stronger mid-range punch, modern suspension.

3. Husqvarna WR250 (2007–2010)

• Pros: Six-speed gearbox, plush seat.
• Cons: Heavier feel, less aggressive geometry.
• KTM Edge: Superior WP suspension, race-ready out of the box.

Verdict: The 250 SX dominates for riders prioritizing weight savings and raw power. Its competitors offer more user-friendly traits but can’t match its intensity.

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Maintenance: Keeping the Beast Alive

Owning a KTM 250 SX means embracing its high-strung nature. Here’s how to keep it running like a champ:

1. Engine Care

• Top-End Rebuilds: Expect to replace pistons every 30–50 hours. Use a quality forged piston kit (available at MOTOPARTS.store) for longevity.
• Carb Tuning: The Keihin PWK thrives with regular cleaning. Swap jets for altitude/temperature changes.
• Cooling System: Monitor coolant levels—this engine runs hot under load.

2. Suspension TLC

• WP Fork Service: Change oil every 40 hours. Upgrade to SKF seals for better durability.
• PDS Shock: Rebuild every 100 hours. Check nitrogen pressure periodically.

3. Critical Upgrades

• Exhaust: A aftermarket expansion chamber (e.g., FMF Fatty) boosts mid-range torque.
• Air Filter: Swap the stock foam for a twin-air filter—less restrictive, easier to clean.
• Brake Pads: Sintered metal pads improve stopping power for aggressive riders.

Pro Tip: Always use synthetic two-stroke oil (1:60 ratio) to prevent seizures. MOTOPARTS.store stocks oils tested in extreme conditions.

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Conclusion: A Timeless Off-Road Weapon

The 2007–2010 KTM 250 SX isn’t just a motorcycle—it’s a statement. It rewards skilled riders with unmatched agility and a powerband that feels alive beneath you. While newer bikes offer more tech, none replicate the primal joy of mastering this two-stroke icon.

Whether you’re rebuilding a barn find or upgrading a well-loved example, MOTOPARTS.store has the parts to keep your 250 SX dominating trails and tracks. From performance mods to essential maintenance kits, we’ve got your back—because legends deserve to ride forever.

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Specifications sheet

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