Bought my Sachs Madass for some idiotic reason and I'm stuck with it for a couple months until I save up some funds for a real bike, meanwhile last night I saw some debates on other forums for specific bikes about which fuel is best. The manual for the bike I own [2010 Sachs MadAss 125] said 91 which is exactly what I've been using for the last month, but a few owners swear by premium. I'll be honest and say I know nothing about fuel, or close to it. Can using premium hurt the bike? Is it healthy? With so many different opinions, and not really being able to find out the facts, It'd be nice to know.