Yet an other air intake.
After taking a lot of time reading the posts talking about the Bonneville airbox on this forum, I decided to remove the snorkel and the restrictor plate on my 2011 EFI Bonnie. Since then, the engine breathes much better.
But the hole remaining in the air filter holding plate could be enlarged a bit more.
So I cut the inner side and fitted a plastiline half round bell mouth to give a better look. I'm not sure that this shape will be "scientifically" efficient as a computed designed velocity stack but this round shape smoothe the airflow better than a sharp one.
I made a flexible silicon mould and cast one with black polyurethane resin. A silicon gasket is fitted on the inner side, where the original one was hiding, to keep the airbox airtight.
After a few experiments with bubbles tracking and elimination, the result is quite solid and fits perfectly.
I was thinking of fitting a wire mesh to prevent things to get in the filter. But I have been using this device like that for a few months and for now, I didn't find any grasshopper, nuts, or Harley Davidson part inside

Even in heavy rain condition, the air filter never seems to be soaked or wet.
Tell me about your experiences with your mods on air intakes.