My mechanic told me quite some time ago to be sure to use an ethanol gas treatment in my motorcycle. He emphasized to use the BLUE (marine) treatment rather than the red stabilizer as it is specific to ethanol gasolines.
I use Star Tron, though Lucas, Stabile, and others are also on the market. It only takes an ounce to six gallons of gas and I use it faithfully in my bike and from day one in the toy hauler. I also use it periodically in my truck, especially when I know it is going to sit for a couple weeks. I find the increased mileage offsets the cost of the treatment.
For more about the problems with ethanol gasoline check out their site http://mystarbrite.com/public/pdf/LIT010V2.1-101.pdf