ive been struggling to find a replacement backfire band for a brc backfire vaulve so today after pondering things 4 a while i took the plundge and got an old innertube from a c 90 moped and cut a strip an inch wide and stretched it over the vaulve to create a expantion point so far it seems to work.the other thing ive done is replaced all the copper elbows and extended them to gain a propper seal and this seams to of cured the backfire problem.thanks to the local plumber he did the extentions for me.all in all so far so good.just hope i can find the propper band seal.