Riding a Road King on I-70 outside of Denver I had one of those "should I or shouldn't I" moments like you're describing. A man tried to cut me off, I didn't budge, and he began swerving at me. He screamed, he shouted, and he drove partially in my lane.
Unyielding to his encroachment, I remember thinking "would he do this if he knew I was carrying 20+ rds of 10mm?" That was my "open carry" moment, FWIW. I had the cruise control on (right hand free) and began running through scenarios in my mind.
As others have said, maneuverability and power are to your advantage. If he had followed me to the gas station...different story. But, he was driving a minivan and that to me is a much worse fate than a 10mm rd to the face.
Any shots from a moving motorcycle would be extremely hard to justify.