Fuel distribution connections?

Embarrassing question:

R1100RT, which fuel distribution tube is the return and which is the supply? I had a plastic/rubber pair marked, but a bit of fuel took the marking off. I know which rubber fuel line is supply and return, but which plastic tube is which? Top or bottom?

I'm installing quick disconnects now so I never have this problem again. But need to get it right this one last time!

The top plastic line is the RETURN line.

The bottom plastic line is the high pressure SUPPLY line.

Put the male half of a QD on the plastic return line and put a female QD on the plastic supply line.

I did reverse the m/f of the lines to avoid the confusion in the future. Does the flow direction actually matter with the QD's?

Thanks for the info.

I did reverse the m/f of the lines to avoid the confusion in the future. Does the flow direction actually matter with the QD's?

 

Thanks for the info.

Afternoon Hotmop

Once connected the flow direction doesn't matter as the check valves inside the quick disconnects are opened either way.

On MOST (BMW or aftermarket) quick disconnects they can be positioned with the flow going in either direction. BUT, there are (were anyhow) a couple of aftermarket non BMW quick disconnects that only had a check valve in the female side so on those a person wanted the female (check valve) on the tank side of the connection so fuel wouldn't run out of the tank when disconnected.

The reasons I suggested installing them as I did was:

—keep from reversing in and out

—same configuration as factory R1150s

—male on distributor return (upper line) is easier to release check valve for return fuel volume testing

Where is the best location to put the connectors?

Here's a foto for you :-

https://s1.postimg.org/9t18nl611b/BMW_Fuel_QDs.jpg

Remember that the crappy plastic Russian-made BMW male connector snaps for fun when you try to pull it apart - on either line.

See what happened to this US-based British rider of a K1200 when his male QD fitting snapped en route - not even when he was fiddling with it :-

AL in s.e. Spain

This shows a better routing option for the R1150 / R1100 RT