2009 RK with 28,000k miles now, went to ride it the other day and noticed a whirling, pigeon cooing like sound, coming from the primary area. This sound was consistent with the MPH not RPM, so did not think much of it. This seemed to get quieter as the bike warmed up. I then noticed that when I pushed the bike into a parking spot at work with the engine off and in neutral there was a soft intermittent growling sound, same area(primary left side). Long story short took it in. HD dealer tech said he could not hear the sound but I did need front wheel bearings. I asked if he had ruled out IPB as being an issue and he said yes. I declined the wheel bearings, as I just replaced them and the bike was smooth as far as the ride was concerned. Picked it up, no diagnostic fee, on the way home bike felt brand new no whirling sound and very smooth. I still don't believe in problems that fix themselves so I got the jack under it checked the bearings on the wheels, all good, then took the primary cover off. It was perfect inside there no metal shavings and no over tight primary chain as I suspected with all the stories I here about the automatic tensioner. One thing I did that I've never done to this bike was let it sit for over a month. So I don't know maybe it was dry somewhere in the trans or primary and needed to be ridden to get it back lubricated. So far everything checks out. Since then Ive put about 400miles on it and still perfect with no leaks or anything. The moral of the story, just ride it. If there is a problem it will be obvious with these machines.

 

I agree totally, these aren't Cinderella machines, they are designed to take a beating...anything subtle is probably not worth worrying about.

 

I had a similar speed related growling that was the mainshaft bearing going bad. My hearing is not that good and I sure don't worry about random noises either.
Take off the right side tranny cover and look in the corners of the case.
Wipe out the dark stuff and rub it on a white rag. You will know.
Captsluggo