I have just returned from a 2600 mile trip to Germany. My Garmin Motorrad Nav 5 was running all the time. On some occasions a a thin "black cloud" would travel at random across the map image. Any one experienced this? I phoned Garmin UK who were helpful and said it could be that this might be due to the length of time the sat nav was connected and the fact that the weather was very hot. I was told to keep using it and if the fault persisted then they would help. Any thoughts or ideas?