Are the carb diaphrams supposed to rotate?

[Incubus]

Around the base in the middle that holds the needle? Of my four diaphrams, two will move around the base and two seemed fixed. I mean you can hold the needle holder and the diaphram will slide around it. Are the fixed ones stuck from age or are the ones that move decrepit with age. If they move and they aren't supposed to, will they still serve their purpose? Other than this movement thing, all the diaphrams are intact and relatively supple.

Thanks,

Patrick

[foreda]

Diaphrams

If you are talking about 78/79 carbs, I do not think the diaphrams are suppose to rotate.

[Bamper]

its been a while scince ive had mine apart but if i rememer correctly dont they have a little tab on the top ring of the rubber that sits in a groove on the carb body so they cannot rotate. but i dont rememer if my rubbers (no pun intended) rotated or not i dont beleave they did. and on another note if they do rotate then that would mean there is a small gap between the rubber and the slide so it might not get the vacume it needs.

[Incubus]

They do have a tab, but I'm talking about when I have them out of the carbs. They will sit still once the carb is closed up, I just don't know if there will be an unexpected air leak that would cause the crab not to operate correctly. If they are supposed to be fixed and they instead move that could mean a seal is broken and air would be getting in instead of the diaphram working right. That's my concern.

[Bamper]

now that i think i back im 99% sure they aren't supposed to rotate if i get a chance later ill pull mine off and check.

[jjwaller]

No they most definitely do not rotate.
They are clamped in place when the top is screwed down.
Make sure they are in place all around the groove in the body and then
screw down the top.

[red bandit]

The rubber diaphram is not supossed to turn on the slide. Unless it turns real easy I wouldn't worry about it. The little hole in the bottom of the slide goes towards the engine.

[Crazcnuk]

The diaphragms are fixed so as to locate the breather hole in the bottom of the slide.

If you look, when they are together, all those holes will be lined up the same in each carb.

[petejw]

There not suppose to rotate,
but you can pull the diaphrams off by cutting the
plastic top ring with a sharp knife and carefully
prying it off, you can then inspect the inside of the diaphram,
ive done this to replace them.