First, I searched the forums and found possible solutions (brake whir, tire cupping, over tightening the belt, etc) so I double checked all of these possibilities and none of them seem to apply.

Here are the symptoms: Only hums when bike/tires are warmed up and can only hear it generally within 25 - 50 mph, above that speed the engine, pipes and wind noise drowns it out. The hum seems loudest around 45 mph but is not directly effected by engine speed (if I squeeze the clutch at 50 mph and coast to a stop the hum will steadily decrease with the speed of the bike, not the engine). Applying the front or rear brakes does not seem to affect the hum either, other than slowing the speed of the bike. The hum seems to be coming from the right side of the bike and most likely the rear wheel, but I am not certain.

Has anyone encountered a similar issue or know what this might be? Please let me know and thanks in advance!

I just replaced my front wheel bearing last weekend. Notice a sort of rumble from the front that wasn't the usual brake rotor noise. Last ride was on really rough roads and the bike didn't coner right and like to have viberated the windshield off. After I replaced the bearing all is good. The old bearing looked OK when I took them out but they must not have been. Mine had sealed bearing because they are after market wheels. Very well could be the bearings.

Don't know if this will help but some tread designs will be more noisey on road surfaces than others. Something to look at anyway.

When I run on tarred strips mine makes a similar sound.

Check your headlight if you haven't already.

Have you tried to just touch the front brake and then the rear? I seem to remember having a vibration from the calipers that sounded like a whirr or hum.

Thanks for the feedback. I've tried just lightly and firmly depressing the brakes to see if that would make a difference or change the hum noise in any way but it hasn't. I also know it is not the tar snakes or other type of road surface since this happens every time I ride now regardless of the surface. Likewise, I suspect it isn't the tire tread either (though possible I guess) because I have had these tires for a few thousand miles and never heard the humming noise until last week. I was in the middle of a 300 mile day trip through northern NH and while cruising down a country road in the mountains at about 50 mph I started noticing the humming for the first time. Since then, I can hear it every time I ride the bike, but it seems only after the bike has warmed up. As I mentioned before, it sounds like it is coming from the right-center or right-rear of the bike. The bike has about 24k miles on it and the wheels are aftermarket, but where installed shortly after the bike was originally purchased. Any other ideas/feedback/suggestions are appreciated. Thanks again.

I've had the same issue since the bike was new (bought as a leftover new 05 in 2007.) The front end noise was so loud with the whisper quiet stock exhaust that it was all I could hear. A trusted bike builder buddy told me it wasn't a bearing and it could be anything from front end design to rotors spinning in the wind to tire noise, and why don't I just try a new exhaust instead?

24k miles later, I really don't know if still makes the noise or not, but nothings fallen off yet. Made the switch to Metzlers long ago (BIG help!) and run a HK Sideburner, so its hard to hear anything else. I may have just gotten used to it though.

Decompression solenoid? At least that's what I think it is on mine. Mine does it all the time but I hardly notice it anymore.

Have you checked the wife on the back seat...

What tires are you running. I noticed a humming sound with the stock Bridgestones when the rear got pretty worn down. Disappeared when I put the Avon tire on! Check you belt tension and if those check out the wheel bearings may be the culprit.