I'm trying build a velocity stack slash air cleaner for Ratty. With minimal thought, I hacked up a piece of foam and started with the fiberglass. I pretty much forgot to snap pics along the way, so here are a couple.
Hunk of foam on the right, carved foamed covered in cloth on the left:
Roughly cut out and set on the carb:
I'll be mounting a screen across the face, then using an aluminum plate to secure it.
Still needs to be cleaned up, sanded, painted etc., but it should look pretty neato, and function as an air filter.