The slow speed vibration could be attributed to a warped front disc. If it's happening when braking at that slow speed then that is the most likely culprit. Like others have said, the higher speed one could just be engine harmonics. I know mine used to have a little between 5.5k to 6k rpm. At least that's where I think it was, it's been so long since I've ridden my speedy and paid attention to it.
