2011 Triple Black 1200GS, now has 7,500 miles. Since new it has made a whoom, whoom noise in 5th gear between 40 & 50 mph. Drop below 40, or accelerate above 50 and the noise goes away. Pull the clutch in and the noise goes away! Change into 4th or 6th and the noise goes away. Makes me think it's a transmission problem, someone speculated it's a bad 5th gear not quite meshing properly. I'm having a challenge getting BMW to investigate the problem and resolve it under warranty - they have 1. suggested that the noise in an acceptable limits (not sure how they define acceptable), and 2. advised the dealer to document the complaint so there's a record of it in the future if there's a major failure. Question to forum members has anyone suffered from this annoying noise, or heard of others who have reported the problem and then got it fixed.
