reservoir

Check this out. New shorty levers with a rounded break reservoir. Aluminum Black Master Levers Set Reservoir Cylinder Clutch Brake Motorcycl Parts | eBay

Hey guys, new here just bought a 57 FZ6 for my first bike and have today changed my brake fluid. I have searched (evidently unsuccessfully) to find out what the rubber hollow mould thing inside the rear fluid reservoir is? It attached to the cap and is like a flexible cup that sits in the fluid...