synthetic oils are superior without question, but are you willing to pay for something you can't really see!! again most "synthetics," most amsoil products included are CRUDE oils with xtra processing classed group III, pennzoils GTL oils are said to be better but also need the extra processing to be classed as group III. group IV + V oils also classed as synthetic are REAL synthetics synthesised, not refined crudes. the group IV PAO oils are synthesised from one hydrocarbon molecule from crude + tailored to the application! group V Ester oils are many generally synthesised from acids + alcohols among other things, this group is costlier to make hence its higher selling price + is usually blended with PAO in superior products. Ester oils are without compare but need another "synthetic" to get the best blend!! group IV + V oils use little to no viscosity index improvers making them last longer while protecting better especially in a shared engine-tranny application. any combination of group III, IV, + V base oils are all legally "synthetic" for marketing + sales in most of the world, USA included!! your $$$ your choice as always. changing cheaper oils more often lessens the inferiority of it + those riding in older + very hot conditions as well as those keeping their bikes a long time benefit most using the best lubricants possible!! happy holidays to all