Fuel pump leakage from third tube?

[LuchikaDeSousa]

Hello everybody,

I'm on this forum even if I'm searching information about my father in law R1200GS STD 2008 because we figured out that his bike is mounting a R1200RT 2010 fuel pump which has run into some sort of problem some days ago.

After filling completely the fuel tank at the gas station and starting the engine, the pump started "to spit out" a lot of fuel from the hose connection you see marked in green in the picture below.

IMG_20240124_223005.jpg (206.75 KiB) Viewed 644 times

On his bike, that hose connection is completely disconnected (no tubings present at all!) and we are trying to figure out what is the purpose of this third tube on R1200RT, to then try to understand what has gone wrong and how to fix the problem definitively.

Thanks in advance for your help, hope this is not a duplicate!

[LuchikaDeSousa]

Nobody?

[David.]

Have I understood this correctly, the bike in question is a 2008 (Hexhead) GS fitted with a 2010 (Camhead) RT fuel pump.

From both the Hexhead and Camhead Haynes manuals, it "appears" that the GS fuel pump does not have the third hose connection. On the RT, this connection is described for both Hexhead and Camhead as a fuel tank drain hose. Perhaps an RT fuel pump should not be fitted to a GS.

[LuchikaDeSousa]

Thanks David for your kindly reply.

Unfortunately the RT pump has been fitted on this GS in 2013 by BMW service, and until 2024 it worked flawlessly.

We experienced a fuel leak for the first time some week ago, so now we're just trying to figure out what happened and where this third hose is expected to be connected on a RT, if it's draining on the floor or if it's returning back in the fuel thank, or whatever.

[David.]

On my 2012 Camhead RT, the third hose drains to the floor.

[LuchikaDeSousa]

Thanks again, this was the information I was looking for!
As far as you know, is this third tube passing near the fuel tank cap before going down to the center stand of the bike? In other words, does it need to be treated like a communicating vessel and go upwards first then down to the floor, or doesn't matter?

[LuchikaDeSousa]

IMG_20240131_080112.jpg (203.89 KiB) Viewed 469 times

From this picture it looks like it is going straight to the floor without further precautions, can you confirm?

[David.]

The third tube passes beneath the fuel tank, there is a tube connector on the side of the air box, from there it continues to ground near the centre stand.