Things You'll Need
Carburetor jet set
Puch mopeds were the popular mode of transportation all over Europe in the 1970s and 1980s. Although you don't see them much anymore, they are still for sale; it just takes some effort to find one. If you own a Puch moped and would like that extra "push" to get around in the streets, keep up with traffic, and finally get to go on that 40 mph road, then you need to upgrade your Puch's engine.
Remove the air filter of your moped by unscrewing the two Phillips screws holding on the plastic box connected to the carburetor of your Puch. This will increase air flow to the engine, resulting in a richer mix in the engine, which gives the engine better acceleration.
Replace the spark plug with a new one. Although you may have a newer spark plug, doing this $5 upgrade will always increase performance, as spark plugs are rarely cleaned completely, resulting in engine performance loss.
Remove the carburetor, and unscrew the top screws holding on the throttle mechanism inside of the carburetor. Once these screws are removed, the throttle cable will pop out of the carburetor, leaving it empty. Soak the carburetor in carb cleaner fluid, and let it air-dry. Give it a few hard knocks to get any dirt out of the carburetor after it is dried.
Locate the small, golden screw with a hole cut in the center of it in the carburetor. It is usually located right next to the throttle cable inside of the carb. Replace this screw with a larger one from your jet set. Experiment with different-sized carburetor jet screws to get more fuel to the engine.
Remove the muffler pipe using your wrench, and locate the small pipe that extends off of the narrow exhaust pipe. This narrow pipe acts as a restrictor; cut it off with your saw, and crimp the hole using the vice. Replace the muffler.
Consider buying a big bore kit, which completely removes your old carburetor, replacing it with a new, larger one. This upgrade will increase your top speed by at least 7 miles per hour.