Isn't the Rotella T6 5w40 diesel oil? Diesel and gasoline oils are quite different and in gasoline motors, also like like atv-s it probably can harm your engine, starting with washing the seal between the cylinder walls and rings and finishing wiht catalytic converter.
As it comes to my opinion then the oil is the cheapest and simplest component and also importan aspect in maintaining engines good health and long life. Due to that there is need to watch for engine manufactures reccomendations for certain oil grade and classification in API class.
It's nice to hear someone else say that. I've argued the use of diesel oils in gasoline engines for years..especially in high RPM, High heat motorcycle engines. They are very different then low RPM, sooty engines, producing entirely different gasses and chemicals in the crankcase and yes, as such, use different materials in seal and other parts..as well as very different operations and sheering needs. But...so many here in the US have been using diesel oils in their gas machines for so long with no "immediate" damage, they all swear by it...and the cost is less. So I gave up in and quit the fight. I won't use it. I pay the extra for a better oil, Castrol Power RS or Power1, because it has everything for the most punished shared sump racing motorcycle engines on the planet....and these Chinese engines need all the help they can get. Besides, my dad always said, "Never go cheap on Fluids and Filters.. cause rebuilds aren't cheap. Make it last". Now I just say- Use what you want as long as it meets the manufacturer's requirements.