[Healeys] HD6 jet diaphragms

[Don]

Looks like I had another diaphragm go out on my HD6's.  I have used both
the blue and black and have not noticed any difference in the time it
takes for them to go bad.  Is it the current gas that is causing these
to wear and tear as they only seem to last a couple of years.  I want to
replace them before I shelf the HD6's and install triple Webber's but
would like to install the best quality that I can.  Any thoughts?
Don
57' BN4