I have run Mobil 10-40 since day one. (Oct 2015) Now at 34,000 miles have not had any problems with the bike at all. I do change the oil and filter every 5,000 miles. May not be necessary to change the oil so often but I do. Last two bikes Harley Fatboy 89,000 miles (2010-2017) and a Truimph America over 100,000 miles (2005-2010) The Harley was sold for $12,000 dollars and runs like a top. The Truimph America was used as a trade in for the Harley and bought by one of the mechanics that worked there. All ran on Mobil oil. Proper maintenance and good oil equals some pretty impressive mileage.