I have always run Belray at 50 to 1 , I currently run a different oil and run it at 70 to 1. Running a 50 to 1 mix you may have to rejet , maybe 1 size smaller since this is a richer fuel mix , a good oil can be run 50 to 1 with no problems as long as the jetting is right . So the question for you is do you want to rejet and save a little money on oil , or spend a little for oil and not have to mess with it.CBX