user manual for a vstar requires you to change your oil every 4000 miles, and your filter every 8000 miles, no matter what kind of oil you use.
Mobile 1 may keep its properties for 20,000 miles without breaking down in a fuel injected water cooled car, with a highly efficient oil filter, but in an air cooled motorcycle with carburetors, the fuel dilution into the oil, the higher temperatures, the contamination for the wet clutch wearing... The engineers at Yamaha determined you need to change your oil every 4000 miles.
Use whatever kind you like, but the cheapest generic oil at walmart meets all of the yamaha requirements.
BTW, motorcycle oil does not have any additives for extended fuel mileage, lower wear - you have to make sure there are no extra lubracants in the oil or it will make your clutch slip. Oil labeled specifically for motorcycles does not have those additives, and its usually more expense (because of something that is NOT in there).
If you look at the round API seal (API service rating doughnut), you want the bottom half of the circle to be blank. Google this if you dont understand what Im saying.
Last edited by KCW; 04-19-2018 at 08:01 AM.