Oscillating Scraping Noise Coming From Front Pulley Area

I got a 2010 Thunderbird with the 1700 with an issue I haven't been able to figure out. It has an oscillating noise, or like a "wub wub wub" sound when moving, it does it at all speeds but less noticeable at higher speeds since it occurs at a higher frequency then and there is alot of other noise to drown it out. The sound and frequency is entirely based on road speed, so braking, throttle, clutch, load, etc has no effect on it. I originally could've swore it was coming from the back so I thought it was a wheel bearing, but after replacing them it still occurs. I've noticed now, after getting it back out, that I can actually feel it (as a slight vibration when the sound occurs) in the foot pegs as it oscillates.

My buddies and I had it on jacks last fall and ran the bike at about 30mph to try to locate the sound, and it seems to be coming from the center of the bike, around the front pulley area (this also rules out anything with the front wheel since it wasn't moving). Any thoughts on what the issue might be?

Here's a video of the sound, nevermind the flailing camera. It also seems to be more prominent on the right side (but not by much), but I obviously needed that hand for the throttle.

 

I just took the cover off to watch it while I rode around the block, and it didn't appear to have any play or anything.

Could this be something with the clutch? How do they sound when they're going out?

 

I haven't looked into replacing the belt yet. Not ruling it out just yet, but I can't think of anything that'd cause the belt to sound like that.

The engine was rebuilt at the dealer about 5k miles ago, so I'd be surprised if it needed replacing. Could be rubbing on something, but it looks like it's clearing all the guards just fine. I might try removing them all and see if it still occurs just incase.

 

I actually figured it out. It's definitely the front pulley bearing. I stripped the front pulley down to the bearing to get a look at it, and it's pretty bad. The cage basically just fell out, and at least one of the balls is broken/worn in half (7-o'clock position in pic 2). Crap load of metal shavings in the outer seal too. Gunna replace the bearing, change the oil, and give it another oil change after another 100-200 miles to hopefully get any remaining metal out.



I just ordered one of these sets to extract the bearing without having to remove the engine and split the crankcase to get the shaft out and pull it, like the service manual expects you to.

 

I haven't looked around the engine too much on this yet, would dropping the sump be doable on the frame? If so, I'll definitely do that. I was going change the oil after anyway, and tear into the filter to check for metal.