Engineered by Xmotos for the minibike, cross motorcycle segment, the 2008 Xmotos XB-21D relies on a 50 cc (3.1 cu in) air-cooled single cylinder, four-stroke powerplant. In factory specification, peak output is rated at 6.7 HP (4.9 kW) at 8,000 rpm, transferring power to the rear wheel through a automatic gearbox. With a specific output of 134 HP per liter, the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.
On the scales, the XB-21D measures 60 kg (132 lbs) dry, translating to a power-to-weight ratio of 0.11 HP/kg (8.96 kg per horsepower). Rider ergonomics and chassis geometry center around a 670 mm (26.4 in) seat height — giving shorter riders and urban commuters confident flat-foot reach at traffic stops, combined with a 1,100 mm (43.3 in) wheelbase engineered for quick, flickable steering geometry. The 3-liter (0.8 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Specific Output
134 HP/L
Power-to-Weight
0.11 HP/kg (8.96 kg/HP)
Standover Height
670 mm (26.4 in)
Engine
Displacement50.0 ccm (3.05 cubic inches)
Engine TypeSingle cylinder, four-stroke
Engine DetailsSingle cylinder, four-stroke
Power6.7 HP (4.9 kW)) @ 8000 RPM
Compression9.7:1
Bore x Stroke40.0 x 39.5 mm (1.6 x 1.6 inches)
Fuel SystemCarburettor
CoolingAir
Transmission
GearboxAutomatic
Chassis
Front SuspensionUpside shock
Rear SuspensionAdjustable Air bag shock absorption
Wheelbase1100 mm (43.3 inches)
Ground Clearance1,000 mm (39.4 inches)
Wheels & Brakes
Front BrakesSingle disc
Rear BrakesSingle disc
Dimensions & Weight
Dry Weight60.0 kg (132.3 pounds)
Power/Weight0.1117 HP/kg
Seat Height670 mm (26.4 inches) If adjustable, lowest setting.
Overall Length1500 mm (59.1 inches)
Fuel Capacity3.00 litres (0.79 US gallons)
Other
StarterElectric & kick
Color OptionsBlack, Red, Green, Blue, Yellow, carbon block, orange
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
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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.
