Join Date: Jul 2013
Location: Gatton, Queensland, Australia
My 2010 DL650 also developed a transmission whine in 6th gear from about 50K. I assume that as you travel far more in 6th gear that those gears have lost the surface that allows them to engage silently.
To me it is like the differential whine of a 1960's car. There is no vibration, and the noise is reasonably quiet but definitely there and I so assume that the gear surfaces have become pitted or worn.
It does not affect my bikes performance and so I ignore it.
2010 Weestrom; 2017 Kawasaki Versys-X300; 1988 Suzuki GSXR1100