airbox modification

[narx]

Hi, my question is, how to calculate airbox air intake area?

This is my setup.
I`m running top perfomances due plus with 21mm dellorto carb, setup is as follows:
-82 main jet, W16 needle fully down, 50 slide, 45 pilot, air screw 3.5 turns unscrewed

I am using stock minarelli airbox (with malossi red sponge) and 2 holes on it , one is the stock intake hole (14mm wide) but I put out the tube and now is 23mm wide and second one 13mm wide. That`s equal to one hole of 26mm.

Carb is jetted very good and bike is running very good also, but i have consumption of 10-12 liter/100km, and i think it`s too much, what do you think? I have yellow top performaces cdi and giannelli shot.
I am using my bike every day on the public roads.

How can I be sure that carb is getting enough air?

Malossi says for their 21mm dellorto, that u have to bore another hole 13mm wide next to stock intake hole, but not to put the tube out, if I do so it is equal to one hole of 19 mm.
Here is the picture how it should look regarding to malossi.

I tried to jet that way but it was much easier when I put the tube out.

Now I am confused, 19mm it`s even less then carb venturi, is it possible to have enough air that way?

Thanks to all who had patience to read and understand this, I know there is many questions here, every answer is gratly appreciated.

 

[airwalk3r]

I think that 10-12 Litres per 100KM is very much if its City Use. If youre satisfied with how your bike runs, you have to agree with it ..

Better accelaration/performance = More Fuel ..

 

[narx]

I think that 10-12 Litres per 100KM is very much if its City Use. If youre satisfied with how your bike runs, you have to agree with it ..

Better accelaration/performance = More Fuel ..

Yes it runs very good.

Come on, any other opinions?

 

[3alfa3]

Malossi says for their 21mm dellorto, that u have to bore another hole 13mm wide next to stock intake hole, but not to put the tube out, if I do so it is equal to one hole of 19 mm.

In Malossi instalation Manual is guide how to modify airbox, but they say that the hole should be same size for both 19mm and 21mm carb.
Strange.