| The purpose of the non return valve in the return line is to ensure that when the pump runs dry, the fuel circuit still contains fuel. No other reason. ( Obvious solution, never let it run dry). But if the Ducati boys have one then you need one, after all they are the wizards.
If you look at the drawings, the fuel tank connections can in theroy be anywhere. The pickup for the pump is at the base of the pump at the low point. the return outlet is also there, but it has been up to the top of the tank and through the "Degasser", then the hose goes back down again.
Douglas. The disconnect fitting is not a non return valve. and your right the sping has nothing to do with anything other than closing the line via the valves in them.
Rob. I'm going to use an inline male plastic quick disconnect inserted into a 20mm adaptor on both conectors. One will have a non return valve. They will be made of al alloy. This will stop the issue of fuel ****ing out the pressure line from the tank when you disconnect it. Have to wait a week or so to see the results.
Griff  | 
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