Engine speed on the highway (65-75 mph) is all over the place, depending on the bike.
Son has an '07 Ducati 800 Supersport that won't get out of its own way in 6th gear at 65- Revs far too low, geared WAY too high, can't accelerate at all. What were they thinking? On back roads, 50 mph or so, he never gets past 3rd gear.
My '92 BMW K100RS revs around 4600 rpms at 70 mph in 5th (5 speed trans), feels ok and will get nearly 50 mpg