Air filter

A question for all you carb experts.
I have a kz1000g that i have converted to carbs, however the air filter does need replacing as i think its the original filter, and is a little dirty. As with every part for this bike its as rare as rocking horse sh@t. 
im thinking of dismantling the old filter and replacing the paper filter with foam, and then gluing it all back together. Would this work, and if so, what type of foam would be a good choice.

If you look at "motorsport" suppliers they do sell foam specifically intended for this purpose

UNI filter foam works well.  I think the green stuff is good for motorcycle filters.

unifilter.com/online-catalog/accessories/

Cheers chaps, i shall look into both of those suggestions.

Just remember if you go to foam you will need to give it a good oiling! I had some good luck using generic air filter foams when rebuilding bread boxes - I always use UNI filter oil on all my bikes and have no complaints-

Mr E,  yep, no problem, will do that. Looked at uni filter products, and i can get them in the UK.

I've used Uni 5/8" green sheet foam to make a new filter for my 84' Honda VF 700S with great results. I oiled it with K&N filter oil, it's what I had and works fine. The bulk sheet was $16 and was enough to make 4 filters.