Fuel system non return valve
 

Does anyone know the opening pressure of the non return valve(Reversion valve). Yes I'm building my own quick disconnect fittings for my carbon fibre tank. I just need to know the non return valves spring rating.

not sure - but I guess it'll just need to be a weak spring behind the ball bearing as the weight of the fuel will help keep it closed anyway. If your making your own set do you intend to knock a few up and offer them up for sale on the site ?? ps let me know if you do and for how much.
cheers

Neil

Why do you need a non return valve? The fuel just goes round and round driven by the pump against the pressure regulator.

Douglas

Ahh, but when you discoinnect the Q/Ds the fuel ****es out on the floor.

Douglas, the Carbon tank needs 2 disconnects 1 each side of the tank, at it's lowest point, so it's a little different to the alloy / steel standard tanks.
In my alloy tank the return side is quite high up in the tank so no opportunity really for all of the fuel to **** all over yer boots...

Neil

Neil, are you able to provide a sketch or pics, because I'm not convinced about your explanations ...
There's no rigid fuel tubes into a carbon tank, compare to steel (no idea about alloy ...)

My couple of Carbon tanks 93 and 94 have got original reversion valve on the return way ...

On all the self sealing fuel connectors I have seen the action of inserting the male portion pushes open a spring loaded plunger valve. A bit like the garden hose connectors. The connector is then open both ways for the fuel. The rating of the spring has no effect on the fuel flow.

Douglas

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

All, I thought that the LHS connector was a non-return valve - it's actually called a 'fuel reversion valve' in the parts book, whereas the other side is just called a 'union', this led me to think it was a non-return type.
I've bought some quick disconnect connectors which are brass and chrome plated from a guy in the states - they have a 90 deg kick in them but they look great and are leak proof on male and female end. They are not directional.
The thread size is not right but a mate of mine is knocking up an adapter to screw into the tank 1st.
I'll post some pics on completion.
cheers

Neil

http://cgi.ebay.com/ebaymotors/Quick...mZ46 16900337

check out his disconnectors.

Neil