If your motor is pretty new I'd stay with 50 to 1 until it is well broken in, then up it to 75 or 80 to 1. No doubt 100-1 would be OK or they would have law suits for wrecked motors, but I never went over 80-1 with Amsoil Sabre Professional. Now I use Opti-2 at 100-1 and really like it.
Silverbear

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Someday when I grow up I will probably lose interest in toys with wheels, but until then...