Hello, so I recently bought a Derbi Senda DRD Racing 50 SM 2009, and it seems to be fully stock. It goes around 47km/h. I am completely new to all of this, so I'm sorry if I'm getting something wrong. My friend has a 2005 Senda Limited edition, with a Ducati unrestricted CDI and 21mm carburetor (originally ~13mm), and goes around 80km/h. As I understand, my bike's CDI is restricted? And it should get changed to an unrestricted one. We're both thinking about derestricting our exhausts, but when derestricting exhaust, what's all of the re-jetting thing about? I have a 17.5mm stock Dellorto carb, so what main jet should I put in? Can't I just adjust the carburetor with the airflow/fuel screws? Would this be a full Derbi Senda 50 derestrict? Would appreciate if someone explained. Thanks .