Sorry for the lame description of the sound. Noticed an odd sound that I first attributed to my front brake rotor as a mechanic I first took it to suggested the rotor is slightly warped, but not in need of replacement yet. Despite that, I've been riding for about 400 miles, and noticed a cyclical low tone squeaky sound between the speeds of 7 to 15mph that corresponds to the rotation of the wheels. It occurs regardless of being on or off the brakes or whether in gear or coasting with clutch in.

So, today I noticed the outer plastic primary drive belt guard was extremely close to the belt. After removing it, I also saw that the backside metal belt guard has abrasion marks on it where you can see the belt is rubbing against it.

Could this be the cause of the sound? More importantly, how should I fix it? I assume it just needs to be adjusted or "bent" away from the belt.

The first picture is a wider shot. The second is showing a paper slid as far back as possible before it gets stuck between the belt and guard. The third is a small metal yard stake to show a bit more context about how the belt gets closer and closer the guard until it completely rubs.
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Now maybe related are the next two pictures showing the edges of some of the belt beginning to fray. Note, this is on the outside of the belt. My guess is maybe it has rubbed against the outside plastic guard. Or, is this normal wear and tear? The bike has almost 13,000 miles, and my understanding is the belt is original.
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