Minibikes
2009Derbi Dirt Boy 50
34 fields on record
The 2009 Derbi Dirt Boy 50 is a lightweight minibike designed for young riders and beginners seeking off-road adventure. Its compact 49cc single-cylinder engine and minimal 47kg weight make it highly maneuverable on trails and dirt tracks. Known for its reliability and ease of operation, this entry-level cross bike excels at introducing new riders to motorcycle riding fundamentals.
- Capacity
- 49.9 ccm
- Engine
- Single
- Gearbox
- 1-speed
- Dry weight
- 47.0 kg
- Seat height
- 610 mm
- Power
- 5.4 HP (4.0 kW)
What’s new for the 2009 Derbi Dirt Boy 50
vs the 2008| Spec | 2008 | 2009 |
|---|---|---|
| Front suspension | Hydraulic fork. 120 mm travel | Hydraulic fork. |
| Rear suspension | Monoshock. 140 mm travel | Monoshock. |
How it rides
Editorial estimate from the spec sheet - not lab tested- Best for
- Built as a small-wheeled minibike for casual backyard or off-road play riding rather than any competitive or commuting use.
- Built for
- A simple, single-speed automatic-feel minibike with a low-revving 50cc engine, offering easygoing, low-stakes fun rather than performance thrills.
- Not ideal for
- Not suitable for highway travel, touring, carrying passengers, or any rider seeking real speed or long-distance comfort.
Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.
Engine
- Capacity
- 49.9 ccm
- Power
- 5.4 HP (4.0 kW)
- Engine type
- Single
- Power/weight ratio
- 0.1149 HP/kg (dry)
- Bore x stroke
- 39.0 x 41.8 mm
- Compression
- 12.0:1
- Cooling system
- Air
- Fuel system
- Carburettor
- Starting
- Kick
- Ignition
- CDI
- Lubrication system
- Oil pump
Transmission
- Gearbox
- 1-speed
- Transmission type
- Manual
- Final drive
- Belt
Dimensions & weight
- Wheelbase
- 905 mm
- Overall length
- 1290 mm
- Overall width
- 519 mm
- Overall height
- 1260 mm
- Seat height
- 610 mm
- Dry weight
- 47.0 kg
- Fuel capacity
- 2.30 litres
- Oil capacity
- 0.60 litres
Chassis & suspension
- Front suspension
- Hydraulic fork.
- Rear suspension
- Monoshock.
- Front wheel travel
- 120 mm
- Rear wheel travel
- 140 mm
Brakes & wheels
- Front brakes
- Single disc
- Front brakes diameter
- 160 mm
- Rear brakes
- Expanding brake (drum brake)
- Rear brakes diameter
- 90 mm
- Front tyre
- 2.50-12
- Rear tyre
- 2.75-10
Other
- Color options
- Black/white
Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.
What changed, year to year
Differences highlighted| Specification | 2008 | 2009 |
|---|---|---|
| Capacity | 50 cc | 50 cc |
| Dry weight | 47 kg | 47 kg |
| Seat height | 610 mm | 610 mm |
| Fuel capacity | 2.3 L | 2.3 L |
Illustrative - generated automatically by diffing the year records already on file, not a manufacturer-published changelog.
Rider Reviews
Common questions
What is the engine size of the Derbi Dirt Boy 50?
The 2009 Derbi Dirt Boy 50 has a Capacity of 49.9 ccm (3.05 cubic inches).
What engine power does the Derbi Dirt Boy 50 have?
The 2009 Derbi Dirt Boy 50 has a Power of 5.4 HP (4.0 kW).
How many gears does the Derbi Dirt Boy 50 have?
The 2009 Derbi Dirt Boy 50 has a Gearbox of 1-speed.
How much does the Derbi Dirt Boy 50 weigh?
The 2009 Derbi Dirt Boy 50 has a Dry weight of 47.0 kg (103.6 pounds).
Shop this bike
Affiliate linksWe may earn a commission from qualifying eBay or Amazon purchases made through these links. As an Amazon Associate I earn from qualifying purchases.
Please log in or register if you'd like to leave a comment.
Own one? Add it to My Garage and write an owner review with an Owner badge.