the ones i have seen do not need a recharge, Boost bottle is a bad name for these little guys if you ask me, all they do, and forgive me if this doesnt come out right, is give the gases that are pushed back towards the carb on the piston up stroke somewhere to go, when the piston gets to another intake stroke those gases are then reused, also reduced the oily filter, i have seen a few around town but i dont see any reason for myself to get one, i dont mind cleaning an air filter once a week it gives me a chance to give the bike a good look over!