2005 KAWASAKI NINJA 250R CARB QUESTION?

I was having some bike issues and decided to take apart my carb to clean it and I found that one of my diaphragms has a huge rip in it which is what I believe to be the problem. When I push up on it no air is pulled through however the other one is pulling perfect.

Anyways question is I am trying to find a new diaphragm and I found decently priced ones for my bike but its only the rubber part. Mine has a plastic part in the middle of the diaphragm that is the part that actually goes into the carb. How do I remove the rubber part only because that is the only part that needs replacing and that I can find for a decent price.

*BONUS* Any suggestions on where I can order a new one for a good price?
Everywhere I am looking calls that plastic piece the slide. I need to remove the rubber diaphragm off of the slide for the part I am looking at.