I'll try to take a video of this. It sounds almost like a bearing or perhaps a belt barely slipping. It does it best when you modulate the throttle a bit around 1500RPM. I'll try to take a video of it in a bit and post it up. Are there any common problems with these? It sounds like it's coming from the front side of the motor on the pass side. I'm almost inclinded to think it's the alternator.