KTM 660 SMC (2003-2004): The Austrian Supermoto That Redefined Street Playfulness

Introduction

When KTM unleashed the 660 SMC for the 2003-2004 model years, it wasn’t just launching another motorcycle—it was dropping a manifesto. This Austrian-built supermoto distilled the brand’s "Ready to Race" ethos into a street-legal package that blurred lines between hooliganism and precision. Built for riders who viewed traffic lights as starting grids and roundabouts as berms, the 660 SMC remains a cult classic. Let’s dissect why this single-cylinder riot still resonates with riders seeking unapologetic fun.

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Engine Performance: The Thumper’s Roar

At the heart of the 660 SMC lies a 654cc liquid-cooled single-cylinder engine—a mill that feels like it was forged in the fires of motocross glory. With 43 Nm (31.7 lb-ft) of torque peaking at just 4,000 RPM, this isn’t an engine that demands revs; it’s a sledgehammer that punishes pavements from idle upward. The claimed 32.9 HP (24 kW) at 6,500 RPM might seem modest on paper, but the delivery is anything but.

The Keihin FCR41 carburetor—a race-bred flatslide unit—snaps open with immediacy, rewarding aggressive throttle hands with a surge that’ll have the front wheel pawing at air in first three gears. Unlike modern fuel-injected engines, there’s a raw, analog charm here. Cold starts demand patience (the manual specifies a 1,450 ± 50 RPM idle), but once warmed up, the engine barks through its aluminum dual mufflers with a mechanical snarl that’ll raise neck hairs—and neighborhood complaints.

What’s revelatory is the torque curve. At 4,000 RPM—where most four-cylinders are still stretching their legs—the KTM is already hauling. This makes city riding a game of lazy shifts and instant overtakes. The 5-speed gearbox, while notchy compared to Japanese offerings, encourages aggressive clutch work (cable-operated, no less) to keep the front end light.

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Handling: A Ballet Dancer in Motocross Boots

With a dry weight of 131 kg (289 lbs) and a wheelbase of 1,510 mm (59.4"), the 660 SMC feels like a trials bike that accidentally grew a license plate. The steel chromium-molybdenum frame, powder-coated for durability, is stiffer than a Monday morning commuter—yet somehow compliant enough to absorb mid-corner bumps.

The 48 mm WP USD forks (285 mm/11.2" travel) and WP monoshock (310 mm/12.2" rear travel) are tuned for aggression. On smooth asphalt, the suspension feels telepathic, translating every lean angle adjustment into razor-sharp direction changes. Crank the bars, and the bike flicks over like a 125cc two-stroke—a trait amplified by the 17" cast wheels shod with sticky 120/70 front and 160/60 rear tires (metric sizes; 2.9"/4.3" tread width in imperial).

But this isn’t a plush ADV bike. Hit a pothole, and the WP units transmit every millimeter of travel to your spine—a reminder that KTM prioritized racetrack readiness over comfort. The 910 mm (35.8") seat height exacerbates this; shorter riders will need to plan stops like a downhill skier plotting their course. Yet, once moving, that lofty perch grants a commanding view of the road—and the perfect vantage point to scout for impromptu curb jumps.

Braking? The 320 mm front rotor clamped by a Brembo 4-piston caliper isn’t just good—it’s obnoxiously overqualified. Two fingers on the lever deliver enough stopping force to compress internal organs, while the rear 220 mm disc offers just enough bite to back it into corners. ABS? Don’t make the KTM engineers laugh.

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Design & Ergonomics: Function Over Fluff

The 660 SMC’s aesthetic screams "compromise" in a language only Austrians understand. Minimal bodywork exposes the trellis frame and oil-cooled engine, while the angular headlight cluster looks like it was borrowed from a dystopian streetfighter. This isn’t a bike for blending in—it’s a rolling middle finger to subtlety.

Ergonomically, it’s a mixed bag. The seat, thinly padded and shaped like a 2x4, makes longer rides feel like a WWE smackdown on your tailbone. Yet, the upright riding position—wide bars, pegs slightly rear-set—is perfect for urban combat. At 9 liters (2.3 gallons), the fuel tank is laughably small (plan fuel stops every 150 km/93 miles), but it keeps weight centralized for acrobatic antics.

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Competition: How the 660 SMC Stacks Up

Aprilia SXV 5.5 (2006-2010)

Aprilia’s V-twin-powered SXV 5.5 delivered 70 HP and a spine-tingling exhaust note. However, its 107 kg (236 lbs) dry weight couldn’t mask reliability issues (oil migration nightmares) and a maintenance schedule fit for a MotoGP bike. The KTM, while less powerful, offered bulletproof simplicity.

Husqvarna SM 610 (2004-2010)

The Husky’s 576cc single made comparable torque but suffered from agricultural vibrations. Its chassis lacked the KTM’s precision, feeling vague during aggressive cornering. Plus, the Brembo brakes were smaller (310 mm front vs. KTM’s 320 mm).

Suzuki DR-Z400SM (2005-Present)

The DR-Z’s 398cc engine is indestructible but anemic next to the KTM’s 654cc brute. With 32 HP and 148 kg (326 lbs), it’s friendlier for beginners but lacks the Austrian’s manic edge.

Verdict: The 660 SMC wasn’t the most powerful or refined, but its combination of lightweight agility and torque-heavy grunt made it the supermoto purist’s choice.

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Maintenance: Keeping the Beast Alive

Owning a 660 SMC isn’t a hobby—it’s a relationship. Here’s how to keep it healthy:

Valve Checks: Every 1,000 km (621 Miles)

The engine’s 4-valve head requires meticulous valve clearance checks:
- Intake/Exhaust: 0.12-0.15 mm (0.0047-0.0059") when cold
Use feeler gauges and a torque wrench (specs: 10 Nm for camshaft bearings).

Oil Changes: Lifeline of the LC4

• Oil type: SAE 10W-50 JASO T903 MA (1.9L with filter)
• Interval: Every 3,000 km (1,864 miles)
  Pro Tip: Replace the NGK DCPR8EIX iridium plug every 12,000 km (7,456 miles).

Carburetor TLC

The Keihin FCR41 loves clean fuel. Use ethanol-free gas if possible, and clean the pilot jet every 5,000 km. For altitude adjustments, the air screw defaults to 2 turns out.

Chain & Sprockets

The 16/38 sprocket combo and 5/8" x 1/4" chain wear quickly under hard riding. Check tension every 500 km (310 miles)—15-20 mm (0.6-0.8") slack.

Brake Fluid & Coolant

• Front/rear brakes: DOT 5.1 (bleed annually)
• Coolant: Use silicate-free ethylene glycol. Drain every 2 years.

MOTOPARTS.store Recommendations

• Upgrade to a DNA oil filter for better flow.
• Swap stock brake pads for Brembo Sintered HH compounds.
• Reduce vibrations with Pro Taper handlebar grips.

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Conclusion: The Supermoto That Refused to Grow Up

The KTM 660 SMC isn’t a motorcycle—it’s a dare. A dare to ignore speed limits, to transform mundane commutes into mini motard stages, and to prioritize joy over practicality. Yes, the seat’s a torture device, the fuel range is pitiful, and the vibrations could loosen dental fillings. But none of that matters when you’re lofting the front wheel past a line of sedans or carving canyon roads with the urgency of a fleeing suspect.

Two decades later, the 660 SMC remains a benchmark for raw, unfiltered motorcycling—a reminder that sometimes, less technology means more soul. And for those willing to embrace its demands, the rewards are limitless. Now, go check those valve clearances.

MOTOPARTS.store—Your partner in keeping the KTM spirit alive. Explore our range of LC4-compatible upgrades today.

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Specifications sheet

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