Aprilia AF1 125 [1988-1989]: A Screaming Two-Stroke Legacy That Still Thrills

Introduction

The Aprilia AF1 125 isn’t just a motorcycle—it’s a time capsule of late-’80s adrenaline. Born in an era when 125cc two-strokes ruled European streets and racetracks, this Italian pocket rocket remains a cult classic. With its race-bred DNA, razor-sharp handling, and a powerband that hits like an espresso shot, the AF1 125 is a reminder of why we fell in love with lightweight sportbikes. I recently threw a leg over a meticulously maintained 1989 example, and within minutes, its character—equal parts charming and feral—had me grinning like a teenager sneaking out for a midnight ride.

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Design: Aggressive Lines Meet Italian Flair

The AF1 125’s design screams “I’m here to race.” Its full fairing—painted in bold ’80s hues like Aprilia’s signature red/white/black livery—hugs a steel perimeter frame, while the low clip-on bars and rearset pegs force you into a committed riding posture. The sculpted 19-liter (5.0-gallon) fuel tank feels narrow between the knees, letting you tuck effortlessly. Even the dual round headlights (a period trademark) look purposeful, like eyes narrowing before an attack.

Build quality? It’s Italian. Some plastics feel flimsy by modern standards, and the switchgear has a utilitarian rawness. But that’s part of its charm—this bike was built to be ridden hard, not pampered.

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Engine and Performance: Two-Stroke Fury

At its heart lies a 124cc liquid-cooled single-cylinder two-stroke, pumping out 27 PS (20 kW) at a dizzying 11,500 RPM. Let that number sink in: this 125cc engine revs higher than most modern 600cc supersports.

Firing it up releases a cloud of synthetic-blue smoke and a metallic braaaap that’s pure two-stroke ASMR. The powerband is binary: below 8,000 RPM, it’s docile, almost sleepy. But crack the throttle past that magical threshold, and the AF1 transforms. The front wheel goes light, the exhaust note sharpens to a scream, and acceleration pins you to the seat until the 12,500 RPM redline. It’s not fast by today’s standards—0–100 km/h (0–62 mph) takes around 6.5 seconds—but the delivery is so visceral, so alive, that speed feels secondary to sensation.

Fueling comes from a single 28mm Dell’Orto carburetor, which demands patience when cold (that 1.5-turn air screw is finicky). But once warm, response is crisp. Just keep the premix ratio tight—Aprilia recommended 2% (50:1) with quality synthetic oil like Motul 710.

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Handling: A Featherweight with a Black Belt

Weighing just 121 kg (267 lbs) dry, the AF1 125 feels like a bicycle with a jet engine. The chassis—a steel trellis with an aluminum swingarm—is stiff yet communicative. Toss it into a corner, and it flicks over with telepathic ease. The 37mm Marzocchi forks and dual rear shocks (adjustable for preload) are softly sprung, perfect for bumpy backroads but prone to wallowing under hard braking.

Tires? The stock 100/80-16 front and 120/80-18 rear (metric sizing; ~2.75" front, 3.0" rear in imperial) offer decent grip, but modern radials like Pirelli Diablo Rosso IIIs transform cornering stability. Brakes—a single 280mm front disc with a twin-piston caliper—require a firm squeeze, but the AF1’s light weight means stopping power is adequate.

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Competition: How It Stacks Up Against the ’80s Heavyweights

In the late ’80s, the 125cc sportbike wars were brutal. Here’s how the AF1 125 held its own:

• Yamaha TZR 125: The Japanese rival made similar power but used Yamaha’s “YPVS” power-valve system for a broader torque curve. The TZR was smoother but lacked the AF1’s razor-edge aggression.
• Honda NSR 125: More refined, with Honda’s legendary reliability. The NSR’s chassis was plusher, but the AF1’s raw feedback made it a track-day favorite.
• Suzuki RG125 Gamma: The wildcard. Suzuki’s rotary-valve engine delivered more midrange, but the RG’s styling aged poorly next to Aprilia’s timeless curves.

The AF1’s ace? Its race pedigree. Aprilia threw everything they learned from Grand Prix racing into this bike—from the aerodynamic fairing to the close-ratio 6-speed gearbox. It shows.

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Maintenance: Keeping the Two-Stroke Flame Alive

Owning an AF1 125 is a labor of love. Here’s how to keep yours healthy—and where MOTOPARTS.store can help:

Engine Care

• Spark Plugs: The stock NGK B10EG (gap: 0.5–0.6 mm) fouls easily if the oil mixture is rich. Keep spares in your toolkit.
• Premix Oil: Use a high-quality synthetic like Motul 800 Offroad at 50:1. Cheap oils lead to piston seizures.
• Cooling System: The tiny 0.8L radiator needs frequent flushing. Replace coolant annually with a silicate-free formula.

Transmission & Drivetrain

• Chain & Sprockets: The 13/37 tooth combo wears quickly under hard riding. Upgrade to a DID 520VX2 chain (106 links) and hardened steel sprockets.
• Gearbox Oil: Aprilia specified 1.0L of 15W-40. Swap it every 3,000 km (1,864 miles) to protect the fragile shifting forks.

Brakes & Suspension

• Brake Fluid: DOT 4 absorbs moisture fast. Bleed annually and consider steel-braided lines for firmer lever feel.
• Fork Oil: The original 280cc per leg of SAE 10W is too thin. Try 15W oil for better damping.

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Conclusion: A Machine That Demands to Be Ridden

The Aprilia AF1 125 isn’t for everyone. It’s temperamental, thirsty, and demands mechanical sympathy. But for those willing to dance on its knife-edge powerband, few bikes deliver such pure, undiluted joy. It’s a motorcycle that rewards skill, punishes laziness, and reminds us why two-strokes—with their smoke, noise, and madness—will always have a place in our garages.

Whether you’re restoring one or squeezing every last RPM from a well-loved example, MOTOPARTS.store has the parts to keep your AF1 125 alive. From NGK plugs to premium chains, we’ve got your back—so you can keep chasing that two-stroke high.

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Specifications sheet

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