Beware of the ratings the manufacturers place on their racks. My bike (260lbs/CRF450x) was way under the manufacturer rating. After one use I could see the center support was sadly under-designed. I Rebuilt/Reinforced and no problems. To keep my bike from bouncing around I drilled two 1/2" holes / one on each side of the bumper (luckily mine is aluminum) and use a tie-down between the rack and bumper to add stability. I do use the little sway bracket provided at the receiver which is suppose to stabilize but the help is minimal. Another issue is the weight rating is across the rack. When you load your bike ALL of the bike's weight is place on one side which is double the loaded share. I use a scissor jack under the load / unload side when I am loading & unloading to make sure I don't exceed the half load of the load rating. I have a buddy that has a heavier bike like you and he installed two receivers and had a custom rack made. Works great for his heavier bike. Also I haul my bike in the front of my Motorhome as I am towing a Jeep or car with bicycles on the rear. Surprisingly my motorcycle stays cleaner (and bicycles when hauled in the front) than in the rear. Good luck it is possible.
rocmoc n AZ/Fld/Baja