The radiator is a Steve Hucks design.
Yes, I machined a little air filter. The filter element is a regular low-density foam.
Here is a picture of how it come out
With this, the project is finished.
I'm very pleased and happy with how it is running.
I will only touch some parts polishing them to give a nicer look.
Thank you for those that followed this project and also helped me with some hints/suggestions.
A special thanks to Steve Hucks that helped me with a 3D camshaft drawing and clearing some drawing doubts I had.
See you on the next project. It will be the V Twin from George Britnell.