No one said ethanol was economic. It is performance in a pump! Its poor man's methanol! E85 is roughly 105 octane, making it a very desirable fuel for high compression applications. It is commonly used for turbo applications because it allows the user run more boost while the engine actually runs cooler. There are downfalls tho, mainly being that when using pure E85 the user needs to tune fuel system 30% richer than regular fuel. E85 is also slightly corrosive like methanol and extra care and precautions must be taken.
BY NO MEANS AT ALL DO I RECOMMEND ANYONE USING E85 IN THEIR ROYAL ENFIELD!!!!!
But as not to get sidetracked, really any pump gas is just fine for a stock Bullet. Ethanol free or 10%, t doesn't much matter as long as it is quality fuel.