KTM RC 125 (2017–2021): A Pocket-Sized Supersport Experience

When KTM unleashed the RC 125 in 2017, it wasn’t just another entry-level motorcycle—it was a declaration that the thrill of track-focused engineering could exist in the A1-license segment. Designed to mirror the aggression of its larger RC siblings, this 125cc machine became a gateway for new riders to taste genuine supersport DNA. After spending a week with a 2020 model, it’s clear why this bike remains a standout in the small-displacement arena.

Design: Aggression Meets Accessibility

The RC 125’s design is a masterclass in balancing intimidation and approachability. With its twin LED headlights, sharp fairings, and orange-accented alloy wheels, it looks like it’s doing 200 km/h (124 mph) even when parked. The steel trellis frame, painted in KTM’s signature orange, adds a racing pedigree that’s rare in this category.

The bodywork isn’t just for show. Integrated turn signals, a slim tail section, and a wind tunnel-tested windscreen contribute to a cohesive aerodynamic profile. At 820 mm (32.3 inches), the seat height is tall for shorter riders but reinforces the bike’s “big bike” stance. The two-tier seat itself is surprisingly plush for a sportbike, though the rear portion is best reserved for occasional passengers.

Engine and Performance: Small Displacement, Big Attitude

The heart of the RC 125 is its liquid-cooled, 124.7cc single-cylinder DOHC engine. With 15 HP (11 kW) at 9,500 RPM and 12 Nm (8.9 lb-ft) of torque at 8,000 RPM, it’s tuned to the legal limit for A1 licenses in Europe. On paper, those numbers seem modest, but the reality is far more engaging.

Power Delivery:

• Low-End: Below 6,000 RPM, the engine feels polite—perfect for city commuting.
• Mid-Range: From 7,000 RPM, the Bosch fuel injection system wakes up, delivering a linear surge.
• Top-End: The real party starts at 8,500 RPM. The engine screams toward its redline with a surprisingly throaty exhaust note, urging you to exploit every gear.

The 6-speed gearbox is slick, though the clutch requires a firm pull in stop-and-go traffic. Fuel efficiency is stellar at 2.42 L/100 km (97.2 MPG), making it ideal for riders balancing fun and budget.

Handling and Dynamics: Born for the Corners

KTM didn’t cut corners with the RC 125’s chassis. The steel trellis frame, paired with a WP upside-down 43 mm fork and WP monoshock, offers a stiffness that rivals bikes twice its price. With a rake angle of 23.5° and a wheelbase of 1,340 mm (52.8 inches), the RC 125 dives into turns with the eagerness of a hungry predator.

Key Highlights:

• Tires: The 110/70-17 front and 150/60-17 rear Metzeler Sportec M5 tires (on later models) provide grip that inspires confidence, even when leaned over.
• Brakes: Bybre (Brembo’s budget line) 4-piston front calipers bite a 300 mm disc, while the rear 230 mm disc handles stability. ABS is non-intrusive and can be disabled for track days.
• Weight: At 139 kg (306 lbs) wet, flicking the bike through hairpins feels effortless.

On a twisty backroad, the RC 125 shines. The suspension soaks up minor bumps without sacrificing feedback, and the narrow profile lets you drag knees without feeling stretched.

Ergonomics and Comfort: Supersport Sacrifices

The RC 125’s riding position is uncompromisingly sporty. Clip-on handlebars place your wrists low, and the rearset pegs position your legs at a near-race tuck. After an hour, your lower back might protest, but that’s the trade-off for its razor-sharp handling.

The windscreen deflects wind up to your shoulders, reducing fatigue at highway speeds (though the engine’s buzz at 100 km/h/62 mph is noticeable). For urban rides, the narrow seat and upright-ish posture (compared to full-blown supersports) make it manageable.

Technology and Features: Surprising Sophistication

For a 125cc bike, the RC 125 packs impressive tech:
- Digital Dash: Gear indicator, fuel gauge, and a shift light that blinks aggressively as you near redline.
- ABS: Standard and switchable—a rarity in this class.
- Lighting: Full LED setup with crisp visibility at night.

The lack of ride modes or traction control is expected, but the simplicity keeps the focus on raw riding engagement.

Competition: How Does the RC 125 Stack Up?

1. Yamaha YZF-R125:

• Similar 15 HP but with a crossplane-inspired engine for smoother power delivery.
• Softer suspension and a more commuter-friendly seat.
• Lacks the RC 125’s track-ready aesthetics.

2. Honda CBR125R:

• 12.8 HP and a milder chassis.
• Upright ergonomics favor comfort over aggression.
• Cheaper maintenance but less thrilling.

3. Aprilia RS4 125:

• 15 HP with a V4-inspired design.
• Premium Öhlins suspension (optional) and quick-shifter.
• Pricier and less dealer support.

Verdict: The RC 125 dominates in handling and visual drama, though rivals like the Yamaha offer a more relaxed ride.

Maintenance: Keeping Your RC 125 Ready to Race

The RC 125 is built to endure spirited riding, but diligent upkeep is key:

Critical Service Items:

1. Oil Changes: Use JASO MA-certified 10W-40 or 15W-50 oil every 5,000 km (3,100 miles). Capacity: 1.5L (1.6 quarts) with filter.
2. Valve Adjustments: Check every 10,000 km (6,200 miles). Intake: 0.08–0.12 mm (0.003–0.005 in), exhaust: 0.13–0.17 mm (0.005–0.007 in).
3. Chain Care: The 520 X-ring chain needs lubrication every 500 km (310 miles). Adjust slack to 50–55 mm (2.0–2.2 in).
4. Coolant: Replace every 2 years or 20,000 km (12,400 miles). Capacity: 1.0L (1.1 quarts).
5. Brake Fluid: Flush DOT 4 fluid annually.

Common Upgrades from MOTOPARTS.store:

• Performance Exhausts: Unlock a deeper growl and shed weight.
• Adjustable Levers: Improve clutch feel for stoplight sprints.
• Sintered Brake Pads: Sharpen stopping power for track days.
• Frame Sliders: Protect those fairings during parking lot tip-overs.

Conclusion: The Ultimate A1 License Stepping Stone

The KTM RC 125 isn’t just a motorcycle—it’s a mentor. It teaches new riders the art of cornering, the importance of maintenance, and the joy of wringing out every last drop of performance. While its 15 HP won’t melt your face, the way it delivers that power—with a side of Austrian attitude—makes it unforgettable.

Whether you’re carving canyons or navigating city grids, the RC 125 proves that passion isn’t measured in cubic centimeters. And when you’re ready to make it truly yours, MOTOPARTS.store has the upgrades to transform this pocket rocket into your personal masterpiece.

Specifications sheet