I used Mobil ! 4T and Amsoil in my old bike. It seemed to shift better with Mobil 1. I think the Mobil 1 flows better as if the Amsoil is a little bit thicker when cold. Since I still have 8 qts. of the Mobil 1 4T, that will be my oil of choice for at least the first two changes on the 14. Motul 4T full syn is reputed to be a top-grade bike oil, although I've never had occasion to try it. Rotella full syn, which is intended for diesels, is a good, cheap alternative to 4T bike oils, but I wouldn't stretch the change intervals with it like you can with a good 4T syn.