my friend has a blaster and it needs a new front sprocket, he wants it to add him more top end speed so i thought he should just get 1 tooth up from the stock, he has a full FMF pipe on it and it seems to give him some extra bottom end. what is the stock blaster front sprocket and would 1 up for the next front sprocket work out with the stock chain and give him more top end? would he have to rejet?