Oil drain plug is most likely an allen. Make sure to use the correct size and the the wrench is fully seat/straight before you torque on it or you may strip the drain plug.
Also note that the buzzing is most likely the shield vibrating but it could also be unbalanced tires. I suggest pulling the weights off the wheels and putting dyna beads or ride-on in the tires.
Retired USAF, IYAAYAS!
2008 V-Star 1100 Custom Bobber project
2011 Crimson XR with Forged Highway Bars / Hard Bags / Passenger Backrest, Ness parts including Smooth Layback Plate Frame/Mount / Rad 3 Mirror / deep cut grips / drivers floorboards /shifter peg / brake peg / passenger pegs. Witchdoctor black rack, Lloydz filter / timing wheel / VFC III, 7Jurock windshield, Drag Specialties seat.