Yes, it is possible to "upgrade".
But that all depends on what bike you have, whether it is dual or single front disk, or drum for some cb's.
Whole front end swaps are possible allowing you to use more modern brake systems as well.
I would suggest doing searches to find threads about people upgrading their brakes.
You will be able to have most of your questions answered that way.
Possible shine the light on a solution that is easier/best for the specific bike you have.
l8r