There was a post, I think in the Miscellaneous section that covered this, if I remember right, the pointers that came out of that, were to completely clean the mating surfaces, then RTV is a good option, if all else, use some lockwire, and fashion a harness from the back of the filter and around the front of the carb body. Are you still using the faux filter covers (cheese graters)?? Those help to keep the filters with the bike even if the filter actually falls off the carb.