I'm breaking in my new G5 Deluxe and my dealer changed the oil ( regular 20 / 50 ) at 300 miles. He advised me to change it again at 600 miles, which I did. and here is the important info : at 1000 miles, I was advised to switch to SYNTHETIC OIL, 20 / 50 , which I did. I've changed filters and cleaned the magnetic plugs each time. I live in California near the coast, so I've been riding in the cooler temperatures and always changing my speed and load conditions i.e. flat ground and mountain roads. The bike is running fantastic ! Hope this helps.