Kawasaki KX 250F [2017-2019]: A Motocross Weapon Built for Precision

Introduction

The Kawasaki KX 250F has long been a staple in the 250cc motocross arena, and the 2017-2019 iteration solidifies its reputation as a razor-sharp machine for riders who demand precision. Designed to dominate tight corners, blast through rhythm sections, and clear tabletops with confidence, this bike is engineered for competitive riders who refuse to compromise. After spending a day throwing this green beast around a motocross track, it’s clear why Kawasaki’s KX lineage remains a favorite among privateers and weekend warriors alike.

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Engine Performance: Controlled Fury

At the heart of the KX 250F lies a 249cc liquid-cooled, four-stroke single-cylinder engine. The DOHC configuration and 13.8:1 compression ratio deliver a powerband that’s both explosive and manageable—a rare balance in the 250cc class. Kawasaki’s dual-injection fuel system (featuring a 43mm Keihin throttle body) ensures crisp throttle response, whether you’re clawing out of a muddy corner or pinning it down a straightaway.

The engine’s character is defined by its mid-to-top-end pull. Unlike some competitors that rely on low-end grunt, the KX 250F rewards aggressive riders who keep the revs high. The 5-speed transmission shifts with a satisfying click, though you’ll rarely need to venture beyond third gear on most tracks. At 2050 ± 50 RPM idle, the engine settles into a steady purr, but twist the throttle, and it transforms into a frenetic scream that’s music to any motocrosser’s ears.

Key Highlights:
- Dual Fuel Injectors: Eliminates bogging during sudden throttle chops.
- Lightweight Crankshaft: Revs up quickly for rapid acceleration.
- Liquid Cooling: Consistent performance even during marathon motos.

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Chassis & Suspension: A Dance Partner in the Dirt

Kawasaki’s aluminum perimeter frame is the backbone of the KX 250F’s agility. Weighing in at 104.5 kg (230 lbs) with fluids, the bike feels flickable through tight berms yet stable at speed. The 1476 mm (58.1") wheelbase strikes a perfect balance between maneuverability and straight-line composure, while the 330 mm (13") ground clearance shrugs off ruts and roots.

SFF Type 2 Forks:
The 48 mm inverted Separate Function Fork (SFF) is a masterpiece. By separating damping and spring functions into each leg, Kawasaki reduces weight while offering 40(!) clicks of preload adjustability. Combined with 310 mm (12.2") of travel, the front end eats up braking bumps and landings with poise.

Uni-Trak Rear Suspension:
The rear shock’s 19-way low-speed and 4-turn high-speed compression damping let you fine-tune for everything from hardpack to sand. Even at stock settings, the rear tracks predictably through acceleration chop.

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Handling & Ergonomics: Built for Attack

Slip into the saddle, and the KX 250F immediately feels like an extension of your body. The 940 mm (37") seat height is accessible for most riders, and the narrow chassis lets you grip the bike with your knees effortlessly. At 820 mm (32.3") wide, the handlebars offer ample leverage for aggressive cornering, while the footpegs sit low enough to maintain stability during hard leans.

The 21-inch front and 19-inch rear wheels (shod with 80/100-21 and 100/90-19 tires, respectively) provide a predictable footprint. At 1.0 Bar (14.5 PSI) tire pressure, there’s enough sidewall flex for traction without sacrificing responsiveness.

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Brakes & Controls: Precision Stopping Power

Kawasaki equips the KX 250F with a 270mm petal rotor up front, gripped by a dual-piston caliper. The bite is progressive, allowing for trail braking into corners—a rare trait in a class where brakes often feel binary. Out back, the 240mm rotor offers ample stopping power without locking up unpredictably.

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Competition: How It Stacks Up

The 250cc motocross segment is fiercely competitive. Here’s how the KX 250F holds its own:

1. Honda CRF250R

• Strengths: Softer power delivery suits beginners; electric start.
• Weaknesses: Less aggressive mid-range; heavier feel in corners.
• KX Edge: Superior suspension adjustability and sharper throttle response.

2. Yamaha YZ250F

• Strengths: Broadest powerband; class-leading reliability.
• Weaknesses: Heavier chassis; less precise cornering.
• KX Edge: Lighter feel and better front-end feedback.

3. KTM 250 SX-F

• Strengths: Cutting-edge tech (e.g., hydraulic clutch); explosive power.
• Weaknesses: Stiffer suspension; premium price tag.
• KX Edge: More forgiving chassis for less-experienced riders.

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Maintenance: Keeping the Green Machine Alive

The KX 250F is a race bike, and it demands respect in the maintenance department. Here’s what owners need to prioritize:

Valve Adjustments

• Intake: 0.10–0.15 mm (0.004–0.006") cold
• Exhaust: 0.17–0.22 mm (0.007–0.009") cold
  Check every 15–20 hours for peace of mind.

Oil Changes

• Capacity: 800 ml (0.85 qt) with filter
• Recommended: SAE 5W-40 or 10W-40 (API SG/JASO MA)
  Swap every 5–10 hours depending on abuse level.

Chain & Sprockets

• Stock Gearing: 13/50 teeth (520 chain, 114 links)
  Upgrade to a DID ERT2 chain for longer life on rocky tracks.

Cooling System

• Coolant: 1.2L of high-quality ethylene glycol
• Tip: Install a high-pressure radiator cap to reduce boil-overs.

Brake Fluid

• Spec: DOT 4
  Bleed annually or when lever feel turns spongy.

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Final Verdict: A Scalpel on Two Wheels

The 2017–2019 Kawasaki KX 250F isn’t just a motocross bike—it’s a statement. From its surgical handling to its riotous engine, this machine rewards skilled riders who push limits. While it lacks some modern conveniences (e.g., electric start), its raw focus on performance makes it a timeless contender. For those looking to extract every ounce of potential, pairing it with aftermarket upgrades (think exhausts, suspension springs, or grippy footpegs) from MOTOPARTS.store will elevate it from great to legendary.

Whether you’re battling for holeshots or carving up local tracks, the KX 250F remains a bike that’s as thrilling to master as it is to ride.

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Specifications sheet

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