Hi there. I picked up a ys 91AC in good shape off of the net that l had to change the cylinder head on. Well l picked up a head as well off of the net. Now a minor problem. I hope. When l took the engine apart there is a clear plastic gasket between the head and the case. It goes under the cylinder sleeve. I cannot get the sleeve out of the head l picked up. I looked up the engine at the central hobbies site and it does not show a gasket located there. So l am wondering. Do l really need it?

Thanks