Since my initiall break in period for my bike is over, I have been able to get on the highway and use the 6th gear. This is great since my last bike always seemed to want another gear once I go over 75 MPH. Maybe I am just not used to it, of it may be my imagination, but it almost sounds like there is a 'knocking' sound when I'm in 6th on the freeway. It is obviously hard to tell with all the noise, but it's running find with no vibration. It almost has the sound of when you are trying to accelerate in too low of a gear, but when I accelerate, no problem. May just be hearing things, I was so used to my 2000 FXDL and all it's sounds, I may just be hearing the bigger engine also.