If you have the misfortune to hear/feel suction when opening your petrol cap after a long journey check your vent pipes are not trapped.
I run a 1150GS 03 model with 1500 miles on the clock and noticed that the petrol cap had slight suction when being opened after a longish run. Didn't think too much of it until I returned from the National Rally of Wales having run several hundred miles that day I returned home to find that the petrol tank had a large dent in it on the left side just above where my Knee would sit.
After several agonising hours trying to think which scum bag could have kicked my bike (I gave in to my cynical side) the penny suddenly dropped "Air pressure" I returned to the garage place my hand over the dent and open the petrol cap.
Hey presto- The dent partially springs back into shape and the tank leading edges now align with the beak mating rubber. However a significant dent still lingers.
Inspection of the vent tubes which run underneath the petrol tank rear support bracket shows that the tubes have overlapped and been pinched between the tank support bracket and frame bracket.
Any gravity fed fuel system would have failed with this problem causing the engine to become starved of fuel, but the BM being fuel injected the pump somehow managed to maintain a supply of fuel.
No loss of power was evident in fact the bike behaved impeccably all day.
1 new fuel tank later and a little re-routing of the pipes, problem solved.
Apparently I am not alone with this issue at least 1 other 1150GS rider has had the same problem.
I run a 1150GS 03 model with 1500 miles on the clock and noticed that the petrol cap had slight suction when being opened after a longish run. Didn't think too much of it until I returned from the National Rally of Wales having run several hundred miles that day I returned home to find that the petrol tank had a large dent in it on the left side just above where my Knee would sit.
After several agonising hours trying to think which scum bag could have kicked my bike (I gave in to my cynical side) the penny suddenly dropped "Air pressure" I returned to the garage place my hand over the dent and open the petrol cap.
Hey presto- The dent partially springs back into shape and the tank leading edges now align with the beak mating rubber. However a significant dent still lingers.
Inspection of the vent tubes which run underneath the petrol tank rear support bracket shows that the tubes have overlapped and been pinched between the tank support bracket and frame bracket.
Any gravity fed fuel system would have failed with this problem causing the engine to become starved of fuel, but the BM being fuel injected the pump somehow managed to maintain a supply of fuel.
No loss of power was evident in fact the bike behaved impeccably all day.
1 new fuel tank later and a little re-routing of the pipes, problem solved.
Apparently I am not alone with this issue at least 1 other 1150GS rider has had the same problem.
