Originally Posted By: Quattro Pete
Amsoil 10w-40 is probably one of the best motorcycle oils out there. Rotella isn't any better, but it is cheaper. However, Rotella may not last as long in service as Amsoil before your clutch starts slipping. So, depending on how often you plan on changing your oil, the switch to Rotella may or may not make financial sense.
sums it up well..