2003 Rieju MRX 50 Pro Technical Analysis & Specification Breakdown
Built around Rieju's enduro - offroad motorcycle platform, the 2003 Rieju MRX 50 Pro relies on a 49 cc (3 cu in) liquid-cooled single cylinder, two-stroke powerplant. In factory specification, peak output is rated at 8 HP (5.8 kW), transferring power to the rear wheel through a 6-speed gearbox and chain final drive. Internal engine geometry specifies a bore and stroke of 40.3 x 39.0 mm (1.6 x 1.5 inches).
On the scales, the MRX 50 Pro measures 94 kg (207 lbs) dry, translating to a power-to-weight ratio of 0.09 HP/kg (11.75 kg per horsepower). Rider ergonomics and chassis geometry center around a 920 mm (36.2 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,332 mm (52.4 in) wheelbase engineered for quick, flickable steering geometry. The 8.4-liter (2.2 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Rieju archive, this model family spans 3 indexed model years from 2003 to 2007, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Power-to-Weight
0.09 HP/kg (11.75 kg/HP)
Standover Height
920 mm (36.2 in)
Engine
Displacement49.0 ccm (2.99 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Power8.0 HP (5.8 kW))
Bore x Stroke40.3 x 39.0 mm (1.6 x 1.5 inches)
Valves/Cylinder0
Fuel SystemCarburettor. Dell´Orto
Fuel ControlReed valve / power valve
IgnitionCDI
LubricationSeparate lubrication with automatic oil pump
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
ClutchMultiplate wet clutch in oil bath
DrivelineChain final drive
Chain Size420
Chassis
Frame TypePerimetral of double beam in steel of high resistance
Front SuspensionUpside Down Front Fork
Rear SuspensionMonoshock Absorder Progressive System
Wheelbase1332 mm (52.4 inches)
Wheels & Brakes
Front Tyre80/90-21
Rear Tyre110/80-18
Front BrakesSingle disc. Galfer double piston
Rear BrakesSingle disc. Galfer
Dimensions & Weight
Dry Weight94.0 kg (207.2 pounds)
Power/Weight0.0851 HP/kg
Seat Height920 mm (36.2 inches) If adjustable, lowest setting.
Fuel Capacity8.40 litres (2.22 US gallons)
Oil Capacity1.30 litres 2T reservoir / 0.80 L gearbox
Service & Fluids
Engine Oil2-stroke synthetic motorcycle oil (API TC / JASO FC/FD)
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
