With all the quality procedures in the world, faulty products do sometimes escape the net and make it to the store. It almost sounds like you got the one they made last thing on a Friday.
I've not heard too much bad said about the F650, so the chances are either you've got the one that got away, or your mechanic stinks. So try another BMW dealership, and if that doesn't fix it, sell it and get another one.
Iain.