The exhaust that you made for the Carablea is nice since it fits under the engine rail guards. If you decide to make another Carabela exhaust like that one to sell, let me know. There were "track like" versions of Carabela Moto pony formula Carabela V1 60CC that had an expansion chamber instead of the V1 pancake exhaust (see attached image).
Since you are starting to tune your Carabela, some Carabela V1 information:
Carabela V1 50cc: Standard 50cc bore (38.8mm piston) Carb Dellorto SHA 14:14L with 52 main jet & stock air cleaner. With a 10tooth front sprocket & 45tooth rear sprocket should go @ 32mph.
Carabela V1 60cc: Standard 60CC bore (42mm piston) Carb Dellorto SHA 14:14L with 56 main jet & stock air cleaner. With a 10tooth front sprocket & 45tooth rear sprocket should go @ 37mph.
In the past, I had a Carabela V1 Standard 50cc bore cylinder (38.8mm piston) that I had a local machine shop bore out to 42mm to make it a Carabela Standard 60CC bore (42mm piston). The Carabela Moto Pony uses the Carabela V1 60cc cylinder with the same 42mm piston setup.