Remove the muffler from your moped by undoing the nuts and bolts that attach it to the bike using a wrench. These bolts will be located in plain sight, usually in the muffler's "can."
Remove the screws holding the muffler can together with a screwdriver. If your moped model has rivets holding the muffler together instead of screws, use a pair of pliers to pull out the rivets.
Pull out all of the noise-reducing stuffing inside of the muffler's can. This material is made to reduce your engine's noise output, so removing it will increase the noise your engine makes. Wear gloves when performing this activity, as this material can cause itching and irritation when it comes in contact with skin.
Drill three holes in the muffler can---one in the tip of the muffler's pipe and two on the sides of the muffler. These holes will create the popping sound that most motorcycles make when accelerating.
Saw off part of the muffler can for maximum noise output. This will increase your noise by quite a bit but it will also reduce your engine's raw power, especially in the mid-range. This upgrade is recommended only for people looking for an especially noisy moped.