George Cels works for Amsoil in USA and dedigns oils for 40 years he runs a thread on DML forum Ducati Monster list, he states time and time again that shear strength and abilty to handle high temp without breakdown are the main factors in good motorcycle oil, so good sythetics are best such as mobil 1 , but that some diesel type synthetics are OK as they have the required qualities, also in air cooled engines that good quality semi synthetic are OK , but that mineral grade synthetic such as shell Advance Ultra are a con , buy real fully synthetic oils Grade IV not the grade III mineral synthetics.
jerry