Rieju 50 MRX Pro (2002-2004) Review: A Pocket-Sized Enduro Legend Revisited

Introduction

The early 2000s were a golden era for lightweight enduro machines, and the Rieju 50 MRX Pro stands out as a feisty contender that captured the hearts of young riders and off-road enthusiasts alike. Designed as a gateway to the dirt bike world, this Spanish-made two-stroke packs more personality than its modest 49cc displacement might suggest. Let’s throw a leg over this nimble machine and explore why it remains a cult favorite even decades later.

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Design & First Impressions

The MRX Pro’s styling screams "ready for action" with its sharp, angular plastics and bold color schemes. Available in eye-catching Yellow, Red, or Blue (later updated to Blue/Silver and Red/Black), it carries the visual DNA of full-size enduros scaled down to a beginner-friendly package. The high-mounted fenders and minimal bodywork give it a purposeful, no-nonsense look that hides its approachable nature.

At 920 mm (36.2 inches), the seat height feels confidence-inspiring for shorter riders while still allowing taller teens to stretch out. The narrow profile makes it easy to grip with your knees – a crucial feature when tackling technical terrain. The 8.4-liter (2.22 US gal) fuel tank sits low, contributing to the bike’s balanced feel despite its compact 1,332 mm (52.4-inch) wheelbase.

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Performance: Small Bore, Big Attitude

Don’t let the 49cc displacement fool you – the air-cooled two-stroke single cylinder delivers its 8 HP (5.8 kW) with the kind of urgency that makes every ride an event. The powerband hits like a caffeine shot, zipping from docile putter to screaming excitement as the revs climb. There’s genuine thrill in working the 6-speed gearbox to keep it on the boil, though beginners will appreciate that it’s forgiving enough at lower RPMs.

What’s particularly impressive is how the engine balances trail-friendly torque with top-end rush. The carbureted setup responds well to tuning – a quality that made (and still makes) this bike popular with tinkerers. While modern four-strokes might offer smoother delivery, there’s an undeniable charm to the MRX Pro’s smoky personality and that classic two-stroke yowl.

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Handling & Off-Road Capability

This is where the MRX Pro truly shines. The combination of a lightweight chassis (estimated 75-80 kg dry weight) and long-travel suspension transforms technical trails into a playground. The front forks soak up rocks and ruts with surprising composure, while the rear monoshock handles small jumps and whoops better than many bikes in its class.

The narrow seat and upright riding position create a natural standing platform for attack positions. At slower speeds, the bike feels almost telepathic – flicking between trees or pivoting on tight switchbacks requires minimal effort. Push harder and the limitations appear: the suspension can feel overwhelmed by aggressive adult riders, and the small wheels (21" front/18" rear) prefer technical terrain over high-speed runs.

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Competition: How It Stacks Up

In the 50cc enduro segment, the MRX Pro faced stiff competition from: - Aprilia RX 50: More road-biased but with superior suspension components - Derbi Senda X-Treme: Higher-revving engine but less low-end torque - Husqvarna WR 50: Race-focused geometry but requiring more maintenance

Where the Rieju carved its niche was in delivering 80% of a competition bike’s capability with 50% of the complexity. Compared to the Derbi’s peaky power delivery, the MRX Pro’s broader torque curve made it more accessible for new riders. While it couldn’t match the Aprilia’s on-road manners, its dirt-focused ergonomics and suspension setup made it the better choice for serious trail use.

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Maintenance: Keeping the Two-Stroke Spirit Alive

The MRX Pro’s simple mechanicals make it an ideal project bike. Key considerations: 1. Engine Longevity: Two-strokes live and die by their lubrication. Use quality synthetic oil at the recommended 2-3% premix ratio. MOTOPARTS.store offers premium options like Motul 710 2T that protect without excessive carbon buildup. 2. Air Filter Care: Frequent off-road use demands weekly checks. Our DNA Replacement Filters offer improved airflow while maintaining filtration. 3. Suspension Refresh: Old seals can lead to soggy performance. The SKF Fork Seal Kit provides OEM-quality replacement parts. 4. Exhaust Upgrades: The stock expansion chamber works well, but the Arrow Pro Race system unlocks sharper throttle response.

Regular maintenance tasks like spark plug changes (NGK BR9ES recommended) and gearbox oil swaps (every 20-30 hours) keep this bike running strong. The lack of radiators simplifies cooling system care – just keep the fins clean!

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Ownership Experience

Living with the MRX Pro feels like owning a mechanical pet – it demands attention but repays it with pure joy. Cold starts require patience (1-2 minutes of choke), but once warmed up, it’ll chug through mud or scramble up hills that would stall larger bikes. The digital dash is basic but effective, with a clear analog tach and odometer.

On fire roads, the bike settles into a comfortable 60 km/h (37 mph) cruise, though vibrations remind you this isn’t a highway machine. Fuel economy varies wildly with riding style – expect 25-40 km/L (60-95 mpg) depending on how often you chase that two-stroke hit.

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Conclusion: Timeless Trail Fun

Twenty years haven’t dimmed the MRX Pro’s appeal. It remains one of the most capable 50cc enduros ever made – a bike that teaches proper riding technique without punishing mistakes. While newer four-strokes offer lower maintenance, there’s magic in the MRX Pro’s combination of lightweight agility and two-stroke character.

For riders seeking an affordable entry into hardcore trail riding or a nostalgic project bike, this Spanish pocket rocket continues to deliver grins per euro like few others. With basic care and the occasional upgrade from MOTOPARTS.store, these machines promise endless dirt-filled adventures.

Ready to revive your MRX Pro? Explore our curated selection of Rieju 50 MRX Pro parts for performance upgrades and OEM replacements.

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Specifications sheet

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