Hi Gadge,
Thanks for pointing that one out for me, honestly didn't think anything for these was still available. You're spot on it's merely the black seal on the end that's required. Might make one that's a tad thicker out of some neoprene sheet that I've got here.
Sadly the most important thing in a Kirby carby is no longer available and that is the main brass butterfly shaft.
Thanks again Gadge.
Cheers,
BB.