your not an idiot so don't use olive oil, if this is the first time you have changed the oil in YOUR bike forks than yes go to a dealer and get SYNTHETIC oil for it, its a high performance bike and it will thank you for it later...or you will thank you...... either way its a better bet to do it that way. For my 636 i use either the kawasaki brand "formulated" (just a fancy way of saying it costs more) for my bike. But MOST of the time the workers at the dealerships are not idiots, just be sure to ask the mechanic in the back with the grey hair telling everyone else what to do and NOT the snot nosed kid at the regester who doesnt know fork oil from penut brittle.
