Aprilia SX 50 SM 2T (2006–2018): A Pocket-Sized Supermoto Dynamo

Introduction

The Aprilia SX 50 SM 2T isn’t just a motorcycle—it’s a gateway drug to the adrenaline-fueled world of supermoto. Produced from 2006 to 2018, this 50cc two-stroke packs a punch far beyond its modest displacement, blending Aprilia’s racing DNA with the accessibility of a learner-legal machine. Designed for young riders itching to carve corners or dominate urban commutes, the SX 50 delivers a raw, unfiltered riding experience that feels closer to a full-sized motard than a "starter bike." Let’s dissect what makes this pocket rocket a cult favorite.

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Design and Build: Big Bike Attitude in a Compact Package

The SX 50’s design screams aggression, borrowing heavily from Aprilia’s championship-winning SXV twins. Its sharp, angular bodywork, twin LED headlights, and high-mounted exhaust give it a race-ready aesthetic that belies its 50cc heart. The steel perimeter frame—a staple in Aprilia’s larger supermotos—provides a rigid yet lightweight backbone (dry weight: 98 kg / 216 lbs), while the 835 mm (32.9 in) seat height offers a commanding riding position.

The chassis is suspended by a 40mm Marzocchi hydraulic fork up front (195 mm / 7.7 in travel) and a steel swingarm paired with a hydraulic monoshock at the rear (180 mm / 7.1 in travel). These components, borrowed from higher-capacity models, ensure the SX 50 can handle everything from potholed streets to weekend track abuse. Lightweight 17-inch spoked wheels wrapped in sticky 100/80 front and 130/70 rear tires complete the supermoto stance, while 260mm front and 180mm rear floating disc brakes deliver stopping power that’s almost overkill—in the best way.

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Engine and Performance: Two-Stroke Thunder

At its core lies a liquid-cooled, single-cylinder two-stroke engine displacing 49.9cc (3.04 cu in). With a bore x stroke of 39.9 x 40 mm (1.6 x 1.6 in) and an 11.5:1 compression ratio, this isn’t your grandpa’s moped mill. The Dell’Orto PHVA 17.5 carburetor feeds the beast, producing 4.9 PS (3.6 kW) at governed RPMs—enough to hit 80-90 km/h (50-56 mph) derestricted.

What truly sets the SX 50 apart is its six-speed gearbox, a rarity in the 50cc class. The closely stacked ratios (1st: 11:34, 6th: 23:22) let you wring every ounce of power from the narrow powerband. Snicking through gears with the wet multi-plate clutch feels surgical, and the final 11/53 sprocket ratio ensures explosive acceleration off the line. Two-stroke aficionados will appreciate the reed valve induction and mechanical oil pump, which minimize smoke and simplify maintenance compared to premix systems.

But be warned: this engine demands respect. Keep it pinned, and it’ll reward you with a raspy exhaust note and neck-snapping surges; lug it, and it’ll bog like a moody teenager. Fuel economy sits around 3.14 L/100 km (74.9 mpg), but expect that to plummet if you’re chasing thrills.

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Handling and Ride Experience: Lightweight Flickability

Throw the SX 50 into a corner, and it’s like flicking a scalpel. The 1365–1406 mm (53.7–55.4 in) wheelbase and 99 kg (218 lbs) wet weight make direction changes instantaneous. The wide handlebars offer leverage for aggressive countersteering, while the 17-inch tires provide surprising grip on asphalt and dirt.

The suspension, though basic, is impeccably tuned for its weight class. The Marzocchi fork soaks up urban bumps with ease, and the rear monoshock stays composed under hard braking. Standing up on the pegs reveals a bike that’s begging to be hopped onto curbs or slid through gravel lots. Braking is confidence-inspiring, with the front 260mm disc offering progressive bite—ideal for teaching new riders trail-braking fundamentals.

Complaints? The seat’s thin padding turns into a medieval torture device after an hour, and the kick-start-only routine grows old in traffic. But these are quibbles in a package that’s otherwise a riot.

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Competition: How It Stacks Up

Derbi Senda DRD X-Treme 50:
Derbi’s answer to the SX 50 shares its two-stroke heart but leans more enduro than supermoto. The Senda’s softer suspension and 19/16-inch wheel combo make it better suited for off-road dabblers, but it lacks the Aprilia’s razor-sharp handling and premium chassis components.

Yamaha DT50R:
Yamaha’s air-cooled DT50R is bulletproof but dated. With a five-speed gearbox and conventional forks, it prioritizes reliability over excitement. The Aprilia’s liquid cooling and six-speed gearbox offer a more modern, performance-oriented ride.

KTM 50 SX:
KTM’s mini-motocrosser dominates dirt tracks but isn’t road-legal. The SX 50’s versatility—commuting by day, tearing up kart tracks by weekend—gives it an edge for riders seeking a streetable machine.

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Maintenance: Keeping the Two-Stroke Flame Alive

1. Two-Stroke Oil: Use a high-quality synthetic like Motul 710 (2% mix ratio). The automatic oil pump simplifies fueling but requires regular inspection for clogs.
2. Gearbox Oil: Swap the 0.65L of 75W-90 gear oil every 3,000 km. We recommend Motul Gear 300 for smoother shifts.
3. Spark Plugs: The NGK BR8ES (0.6–0.7 mm gap) is critical for crisp ignition. Carry spares—two-strokes are plug-fussy.
4. Chain Care: The 11/53 sprocket combo wears quickly if neglected. Clean and lube the chain every 500 km with Motul Chain Paste.
5. Cooling System: Flush the 0.85L coolant annually using Silkolene Pro Coolant to prevent corrosion.
6. Brakes: DOT 4 fluid absorbs moisture; bleed every two years. Upgrade pads to EBC FA55/FA181 for sharper bite.

Pro Tip: Monitor tire pressures religiously—1.8 bar (26 psi) front and 1.9–2.2 bar (28–32 psi) rear. Underinflation kills handling; overinflation sacrifices grip.

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Conclusion: A Cult Classic for the Bold

The Aprilia SX 50 SM 2T is a rare breed—a 50cc machine that doesn’t condescend. It’s raw, rowdy, and unapologetically analog, offering a purity of ride that’s vanishing in today’s tech-cluttered market. Whether you’re a novice honing your skills or a veteran craving a back-to-basics thrill, this Italian pocket rocket delivers grins per euro like few others.

And when it’s time to tweak, rebuild, or personalize your SX 50, MOTOPARTS.store has you covered. From NGK plugs to Motul oils, we’ve got the essentials to keep your mini-moto madness alive. Now go carve some corners—and try not to laugh too maniacally under your helmet.

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Specifications sheet

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