If they're the one I'm thinking of, you just need to remove the carbs, and fit the washers between the carb outlet and the head intake rubbers.
Seat and tank off, battery out, slacken the screws on the carb rubbers (airbox side), slacken the 3 bolts holding the airbox in place and slide back, while prising the rubbers off the carb intakes. Undo the screws on the other side of the carbs, slide the carbs back (and off their rubbers) and hey presto.