Derbi 50 Senda [2018–2022]: A Pocket-Sized Supermoto Revolution

The Derbi 50 Senda, produced from 2018 to 2022, represents a bold fusion of youthful energy and precision engineering. Designed as a gateway to motorcycling for new riders and a playful companion for experienced ones, this Spanish-built two-stroke machine carves its identity in the supermoto and enduro segments. After spending time with multiple variants — including the SM Limited, X-Treme, and Racing editions — it’s clear this isn’t just a “beginner bike.” It’s a spirited performer that rewards skill and invites customization.

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Engine Performance: Two-Stroke Thrills, Modern Compliance

At its heart lies a liquid-cooled 50cc single-cylinder two-stroke engine, a rarity in an era dominated by four-strokes. The 39.9 x 40.0 mm bore and stroke configuration delivers a 11.5:1 compression ratio, fed by a Dell’Orto PHVA 17.5 carburetor. While Euro 4 emissions standards have tamed some of the raw edge traditional to two-strokes, the character remains unmistakable.

Key impressions: - The kickstart ritual feels primal — no electric start here — but becomes second nature after a few tries. - Power builds linearly from 6,000 RPM, with a satisfying surge around 8,000 RPM that pulls strong to the 11,500 RPM redline. - The 6-speed gearbox is a standout feature, allowing 70–80 km/h (43–50 mph) cruising on backroads while keeping the engine relaxed. - Fuel efficiency averages 3.14 L/100 km (74.9 mpg), though aggressive riding can drop this to 4.5 L/100 km (52 mpg).

The liquid cooling system (uncommon in small-displacement two-strokes) prevents heat soak during sustained rips, while the automatic oil mixer eliminates premix hassles. Riders craving more punch can explore aftermarket exhausts and reed valves, but even stock, it’s far from lethargic.

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Chassis & Handling: Supermoto Agility Meets Enduro Toughness

Derbi’s twin-tube steel frame forms a rigid backbone, with suspension components that defy the bike’s entry-level status:

• Front: 41 mm upside-down forks (240 mm travel / 9.4 inches)
• Rear: Steel swingarm with hydraulic monoshock (200 mm travel / 7.9 inches)

On-road behavior:
The SM models’ 17-inch wheels (100/80 front, 130/70 rear) offer razor-sharp turn-in. Leaning into corners feels intuitive, aided by a 34–35-inch seat height that keeps weight low. At 104 kg (229 lbs) wet, flicking between traffic gaps is effortless.

Off-road capability:
The X-Treme R enduro variant swaps to a 21-inch front/18-inch rear setup (80/90-21 and 110/80-18 tires). Combined with 170–195 mm (6.7–7.7 inches) of front travel, it handles light trails competently, though serious mud requires tire upgrades.

Braking notes:
- Single 220 mm discs front and rear provide adequate stopping power.
- The dual-piston front caliper lacks initial bite but offers progressive feel — ideal for new riders.
- Experienced pilots might crave braided lines or sintered pads for track days.

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Design & Ergonomics: Aggressive Aesthetics, Approachable Proportions

Derbi’s designers nailed the “miniature race bike” aesthetic. Sharp bodywork, exposed frame tubes, and motocross-inspired plastics give even stationary Sendas a crouched, ready-to-pounce stance. Year-specific color schemes range from Racing editions’ neon yellows to the X-Treme SM’s military camo.

Comfort highlights:
- The stepped seat (860–880 mm / 33.9–34.6 inches) accommodates taller riders better than most 50cc bikes.
- Narrow midsection allows easy ground reach — a boon for shorter inseams.
- Digital dash (on 2020+ models) provides a modern touch with gear indicator and fuel gauge.

Quirks to note:
- Kickstand placement occasionally interferes with boot movement during aggressive cornering.
- Supermoto mirrors vibrate excessively above 60 km/h (37 mph) — consider bar-end replacements.

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Competition: How the Senda Stacks Up

1. Aprilia SX 50 (2018–2022)

• Similar two-stroke engine but with weaker midrange.
• Softer suspension suits casual riders but bottoms out under hard use.
• Derbi’s 6-speed gearbox gives better highway flexibility.

2. KTM 50 SX

• More powerful (8 hp vs. Derbi’s 6.5 hp) but strictly off-road focused.
• Requires premix fueling — less practical for daily riding.
• Higher maintenance costs.

3. Yamaha DT50X

• Four-stroke reliability but lackluster performance.
• 5-speed gearbox limits top speed.
• Heavier at 112 kg (247 lbs) vs. Derbi’s 99–104 kg.

Verdict: The Senda strikes a unique balance — tame enough for city commutes yet tunable for weekend hooliganism. It’s the most versatile option in its class.

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Maintenance: Keeping the Two-Stroke Alive

Critical service intervals:
- Piston rings: Replace every 3,000 km (1,864 miles) if ridden hard.
- Coolant: Flush annually; the small radiator (1L capacity) is sensitive to air bubbles.
- Carb cleaning: Mandatory every 6 months due to ethanol fuel gunk.

Upgrade recommendations from MOTOPARTS.store:
- Arrow Race exhaust: Unlocks ~2 hp and enhances throttle response.
- Brembo PS13 brake pads: Improves stopping power without master cylinder upgrades.
- Progressive-rate fork springs: Reduces nose dive during hard braking.

Common issues to watch:
- Kickstart idler gear wear: Listen for whining noises during startup.
- Chain tensioner slack: Adjust every 500 km (310 miles) to prevent drivetrain snatch.
- Stator coil failures: Symptoms include weak spark and charging problems.

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Conclusion: The Last of a Breed

The Derbi 50 Senda’s 2018–2022 run may well be remembered as the sunset of Euro-compliant two-strokes. What it lacks in outright power, it compensates with character and adaptability. Whether carving canyon roads, navigating urban jungles, or exploring gravel backroads, this plucky Spaniard proves that displacement isn’t everything. For riders willing to embrace its old-school soul — and MOTOPARTS.store’s treasure trove of upgrades — it’s a motorcycle that grows with your skills, demanding nothing but enthusiasm in return.

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Specifications sheet

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