The old SOHC 750 Honda is an unusual Japanese four-cylinder bike in that it uses a dry sump lubrication system. Before the engine comes out these two oil pipes have to be disconnected. One pipe is the oil feed into the engine and the other is for the return to the tank; it's essential that they aren't connected up the wrong way round. Honda have designed these two bolt-on alloy unions so they can't be inadvertently swapped over, so after draining the tank I can simply unbolt them from the crankcase. Note the O-rings which seal them to the casing