Honestly... ride with only one hand holding the steering. You will see it. It does not sit perfectly straight. Every one of your bikes will do it, it is very slight, but is there.
It is something, I never noticed until I was paying attention, but from that point, I see it on all bikes.
I've ridden for miles at 80 with the cruise set and no hands on the bars.. mine definately does not wobble.
You may just be causing it with the one hand if you are putting weight on your wrist.