Air filter question

[fromos]

Hello guys this may seem like a newbish question I've been reading BSH for a while and recently watching cafe racer on sky and I've noticed they use a airfilter im unfamiliar with I no what the stock filters look like on most bikes and the mesh type k and n but what the stainless steel ones that look like the end of a exsaust with the mesh inside they look hollow any links or anything would be apreciated

Usualy found on the vintage bikes.

[Tango]

I think you are talking about velocity stacks. ...a trumpet shaped metal device.....sometimes with a mesh grille across the end. Doesn't filter the air at all......so not very practical for a road bike.... was popular with old race bikes.....that needed an engine rebuild after every race....lol.

[mattycoops43]

Tango's right, but a lot of performance engines still use them, but underneath a foam sock filter. the stack is shaped to improve velocity into the carb and increase power. BMW's etc have them inside the air filter/manifold system.

[fromos]

Cheers guys I was just intrested in them maybe learn stuff about them they must be a bit tricky to fit I assume I just use k an n myself they look pretty old school thanks alot guys much apreciated