Hy guys,   sorry for the late reply and thanks for the nice welcome!   Yesterday I had some time to pump out the old petrol and to remove the tank from the VF. I disassembled than the petrol tap because I thought it´s maybe clogged but finally it looked ok. I found a dent on the lower side of the tank but it seems this is just from putting in the petrol spigot at the gas station. (By the way, I am not sure that I am always using the correct vocabulary so please correct m