problem with adventure

["Richard Wolters" <ricwolt@xxxxxxxxxxxxx>]

Hello, I am new (1 day) to the list and trying to work out how it works. I
hope someone can help with the following problem. Over Easter i bought a 2003
R1150 Adventure 2300 km away and rode it home. The owner is a personal friend
and told me that it had a problem. With Normal riding (100-130 km/hour)
everything fine. When i come to a town and slow down to 60 km/h the bike
starts to misfire , surge,splutter, cough backfire etc. If i stop at traffic
lights the engine sometimes cuts out.

My friend told me that the local BMW workshop had placed the fuel filter
outside the tank by his request. Nothing wrong with that, however it was from
that time on that the bike seemed to play up.
The bike has done 43000 km and has had it 40.000 km service.
Does anyone has any ideas where to sart looking and /or what the problem could
be?
kind regards
Ricwolt- Brisbane Australia