If I´m understanding well your description you must be describing the choke reliefs. These have a rubber gasket that is supposed to be pliable to work. If The´re not pliable they need to be replaced. OR, if the´re in one piece they could be salvaged by removing them from their position and soaking them in a glass bottle filled with brake fluid for at least 5 days . Note: I use this technique to restore any hardened rubber on my vintage bikes i.e. carb boots, rubber washers, and rubber components that are salvageable. hopen this helps, BEARR045