Need help with my seat

Does the standard seat for a 77 KZ1000 have a styrofoam core with foam on top of it, or is it just foam? My bike had an LTD seat on it when I bought it. My wife and I stripped it down to the seat pan and put new foam on it from an upholstery shop, then covered it with a standard seat cover. It looks great, but is not near firm enough. The LTD seat had a styrofoam like core with regular foam on top of it. Did I mess up by getting rid of the styrofoam core? If so, where can I buy a new one?

Thanks

try this...
tinyurl.com/6jg2ul

Thanks, I had looked at that. I was trying to go cheaper than that, but like most things I probably should have just bought that foam and been done with it!

I've been searching the archives and found a post where a guy had used the foam that you put under your sleeping bag when camping. I wonder if I could use a few layers of that and then the regular foam. I have an old camping pad that I might cut up and try. I want this seat to be firm when I'm done with it.

Any other ideas?
Thanks again.

I swiped this from another thread. I don't remember who posted it but the credit should go to him.

www.foambymail.com/index.html