Active 50 Engine
Some of the green engine cover has been removed in order to install a tuned pipe.

The [[Active]] 50 engine is a larger (for a scooter) two stroke engine produced by Active, an Italian engine manufacturing company.


  • Displacement: 51.7cc
    • Bore: 44mm
    • Stroke: 34mm
  • HorsePower (Output): 4.5hp
  • Net Power (kW)r: 3.4kW
  • Rotation (Recoil Side): Clockwise
  • Clutch Diameter: 78mm
  • Ignition System: TCI
  • Max RPM: 11,000 RPM
  • EPA Compliant: no
  • C.A.R.B. Tier II Compliant: no
  • Fuel Type: Unleaded 92+ octane
  • Recommended Fuel Mix: 60:1 (synthetic)


There are currently no distributors in the US.

Performance Enhancements

Tuned Pipes

Puzey Power Pipe

The Puzey pipe was designed specifically for use with this engine on the Evo 2x scooter. Because of this, no modifications should be necessary to adapt it. On Active's 50cc, the Puzey pipe will cause a significant increase in low-mid range power, but will not increase RPMs noticeably.

ADA GSR40 Pipe
Tanaka 3 Piece Pipe


Porting is somewhere this engine really shines. This engine is no toy to begin with, but porting can squeeze quite a bit more out of it. With a skilled hand, ported actives have lived long lives pushing stand up scooters to the 50s.

Head Kit

A few builders have modified the ADA Pocket Bike Headkit to fit on top of Active's 50cc with substantial results. It is not a direct bolt on, but is a close fit.


This engine comes with a high performance carburetor, stock. It is rated for a 15mm venturi, but only has a 13.5mm throttle body. At the time of writing, there are 15mm throttle bodies available for around $15. Performance increase from switching to a larger throttle body is speculated, but not tested.

History with Evo's 2x

Active's 50cc engine became popular with the scooter community when the Evo 2x was introduced with the motor. Evo eventually was forced to stop selling the motor with the 2x due to EPA Restrictions.

Industrial Applications

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