This is copy and paste from loudhvx in another post with the same question
The only aftermarket support the 440's have, luckily are new diaphragms for the carbs.
Very closely inspect them for rips right near where they attach to the slide. That is often the first area that rips.
If they have holes, that will cause bogging. There are many other causes for bogging, but that is one, and a common one on the 400/440's.
There is a place called JBM industries that makes diaphragms.
