I found this while surfing around they can fix your old diaphrams on the slides but let me warn you it is not cheap... 175 per slide OUCH :shock: :shock: but it will be fixed!!!!
http://www.motorcyclecarbs.com/Honda_CV_Carburetor_Diaphragm__W33C831.cfm
Anyway here is the link
I have seen a British site that sold replacement slides and diaphrams, just can't find it right now.
Here seems to be an alternative.
http://www.kawasakimotorcycle.org/forum/vintage-motorcyle-info/92592-carburetor-diaphragm-repair-works.html
Yeah that had the british site way better prices than the one I had shown...