Steering damper on a CB750 is an improvement. My bike could get som wobble above 100mph. Low speed as mentioned earlier like bad wheels, tires, swing arm bearings.
Or during touring with passenger, bags, luggage rack with tent, kitchen sleeping bags etc. It could be instable going upwards in heavy slopes, or just accelaration.
I had bad handling when I had longer fork (+6") and no fork brace, no oem fender that kept the fork legs together.
I think I'll change the frame bracket.