I have never felt the need to purchase any of those (expensive) "ethanol-free", "aviation gas", "race fuel", etc. For the last 16 years I have used regular, unleaded, (ethanol-laden) gas they sell in California, HOWEVER....
I have always used "Stab-Bil Storage Fuel Stablilizer" in ALL of our bikes and equipment. Never had a single problem while using it and some of this same gas has been in the fuel tanks and carbs for over 1.5 years. A little goes a long ways as only a couple of ounces of this will treat 5 gallons of gas.
https://www.amazon.com/STA-BIL-22214-Fuel-Stabilizer-Fluid_Ounces/dp/B000B68V6I?th=1
Michael