R1150 -Cutting out at low speed-Help !

[Motorbike Mike]

Hi All, After a very wet ride and being left out overnight in heavy rain my bike has developed a fault. At low speed as I pull away the bike is intermittantly cutting out, as soon as I hit the start button she fires up again.The cut outs are just like the kill switch is being switched to off then back on just long enough to kill the engine, there is no juddering, one minute fine the next dead. At speed over 15mph the bike is completely normal. It is not cutting out as soon as I put it in gear but as I am rolling along at low revs. The bike has dried out but the fault remains. Any help would be much appreciated.
Mike

 

[Spout]

Probably doesn't fully fit with your symptoms, but check the sidestand cut out switch for crap that could be lurking.