On my R 30mph would be in 2nd or 3rd gear. 40mph 3rd gear maybe 4th; 50 4th gear. 60 4th or 5th depending on the road, corners etc etc.
But just play it be ear, by how the bike feels. If its not pulling nice and crisply change down. If it feels or sounds like you are thrashing it either start grinning or change up. They are great bikes that thrive on being revved hard. Enjoy.
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