On US models, BMW has installed a charcoal canister to capture any fuel overfill. This is an EPA requirement but BMW's solution is a really bad design. This video does an excellent job of explaining why and how to remove this unnecessary assembly of parts. Aside from it interfering with installation of some aftermarket shocks and exhaust systems, it is basically crap and looks crap too.
This link speaks specifically to the solenoid that opens the valve when the engine is running. (this is the part you see Chris in the video pull off and chuck to "clean things up" as he put it. No fault codes will be generated as its a simply on/off switch.
Charcoal canister solanoid - BMW R1200GS Forum : R1200 GS Forums
And here is a nice PDF that provides a bit more detail in the pics.
[No longer available]
This link speaks specifically to the solenoid that opens the valve when the engine is running. (this is the part you see Chris in the video pull off and chuck to "clean things up" as he put it. No fault codes will be generated as its a simply on/off switch.
Charcoal canister solanoid - BMW R1200GS Forum : R1200 GS Forums
And here is a nice PDF that provides a bit more detail in the pics.
[No longer available]