Scooters are available in a variety of brands. However, a lot of these brands use the same engine as a basis. For instance an Aprilia Rally uses the same Minarelli engine as a Yamaha Aerox. To give an impression the most used engine types are shown below:

Minarelli (horizontal):
This engine forms the basis for a wide range of scooters. Aprilia, Benelli, Beta, Malaguti, MBK and Yamaha have models in their range which use this engine.



Minarelli (vertical):
The most popular scooter applied with this engine is the MBK Booster.




Peugeot:
Peugeot develops their own engines. Most Peugeots use the standard Peugeot engine. Peugeot also has an injected version, this is the Peugeot JetForce engine.



Piaggio:
Piaggio engines are used for Piaggio and Gilera scooters. Piaggio also has an injection engine which goes under the name PureJet or DiTech. This engine forms the basis for models such as NRG PureJet, but also for the Aprilia SR DiTech.


Aprilia:
Aprilia engines are mostly used by Aprilia and Suzuki. The injected version, the DiTech engine, is used in the Aprilia SR50 DiTech. However the DiTech is suited with the Piaggio PureJet/DiTech engine, so make sure which engine forms the basis of your DiTech before ordering an exhaust!