Haa Haaa - this old beauty again eh?
I have so many links in my favs folder I cant remember the source anymore but, I think the basics are for a bike with a K&N / freeflow filter and a Stage 1 dynojet kit that you have the option of either:
Running with the airbox lid removed or
Drilling the living daylights out of the original lid.
I chose the latter and tested my new cordless drill
Here is an aftermarket frame that Dr.Desmo has constructed:
http://www.drdesmo.com/airbx.htm some info :
http://www.ducatitech.com/2v/aftermarket/fuel.html a bit more:
http://arch.home.texas.net/ss/history.html and at last I found the site I was finally thinking of:
http://ccrma-www.stanford.edu/~peer/...c-jetting.html 
Have Fun - Frank