My naked GS500 would normally cruise easily at 85 mph (indicated) and go over 100 mph, but one time going against a stiff headwind, it topped out at a steady 6,500 rpm in 6th gear, 75 mph, with the throttle wide open. Wouldn’t go any faster. That gave me a real lesson on aerodynamics, wind resistance and horsepower. I never expected or experienced drag-limited top speed at only 75 mph before that. But think of it this way – if the headwind was blowing at 30 mph, my effective air speed was 105 mph.
It felt so weird to top out at 75 mph w/ WOT I didn’t even think of down shifting to go faster. A guy at work told me he thought he had engine trouble that day when his cruiser (Honda VTX 1300) reacted very sluggishly to the throttle but it was the strong wind.