Most of the reason for pull is a side to side weight imbalance. As little as five pounds can keep you from hands free riding. To counteract this there is often a rear wheel offset on the R1150, each 2.5mm of rear wheel offset counteracts about 5 lbs. of side to side weight imbalance. Try adding 5 lbs, at a time to the side opposite the pull and see how much it takes. Here is where I ended up on my 1150RT.