I just purchased a 2009 Electra Glide. I am new to riding Harleys so I was wanting to know if its normal to have more vibration if you are running at low rpms. Seems to vibrate more at or below 20 rpm. Smooth's out when higher. Also, I filled up with 91 octane and I think it was running smoother with the gas that was in it when I bought the bike. However I don't know what kind it was. Maybe I should try some Sea Foam. Thoughts?