[Darren69]

Originally Posted by Dukedesmo

In a 916 tank the filter is in the tank as is the regulator so the fuel is filtered, pumped out and returns to the tank to face the regulator on return, this creates the correct pressure in the 'loop' and therefore at the injectors . As such the orientation of the out/in lines makes no difference whatever as the fuel is always filtered on the way out.

I believe (at least some) Monsters are different? my (carby) Monster has a fuel-injected model tank and it too has an internal filter but no regulator.

I have set it to circulate a loop which has a 'T' (actually a 'Y') to feed the carbs and the excess fuel just returns to the tank but (I believe) the fuel injected Monster it originates from has an external regulator built into the throttle body assembly? In which case the out and in would matter otherwise you'd be pumping fuel to the backside of the regulator and not getting to the injectors? It would still be filtered though.

That's how my S4 is; the pressure regulator is between the throttle bodies and the filter is in the tank. I'm not sure but I imagine it is filtered before being sent to the injectors so as to protect them from particulate matter either from the fuel or the tank.