The power is interesting around 3000/4000rpm (~50 to 70km/h in 6th) and over 6000rpm (up to 100km/h). But if you ride between 80/100km/h in 6th, you can't overtake or go up the hills; you must down to 5th or 4th. This behavior remember me my Yamaha RD350 (1975 model): heaven over 6000rpm, nothing under 5000rpm. At least, with de CB400Four you can ride through towns on 5th or 6th silently and without smoke...