IMO it really depends on what your setup is and how much abuse the clutch can handle. Ideally you would have the clutch engage about 1k before you "came onto your pipe". This would allow the clutch to fully engage right before the powerband. Granted with some of the high rpm powerband pipes out there this would just destroy the clutch lining. When I was fiddling around with a 2 shoe in my rigid I found that between 360 and 720