I want to do my first oil change soon and so here's the often heard question: which oil to choose? I know my SM450R has Agip Racing 10W-60 full synthetic from the factory but my dealership gave me some Castrol Act-Evo semi-synthetic 10W-40 to use since it costs half as much. Is this better or worse for a street tard?
I know that the second number implies oil thickness at high temperatures so the Agip is made to stay thicker at higher temps. However, I've heard many people in the sportbike forums saying to never put full synthetic in an engine that is still under a few thousand miles. I'm not sure how an 4-stroke supermoto would be any different. Can anyone help me out here?