Air filters, carburetors, and spark plugs
- A dirty air filter can bog down the performance of a moped. Install a new air filter or even upgrade by buying a larger one that allows more airflow to the engine. Similarly, dirty fuel jets inside the carburetors will inhibit engine performance and thus speed. Jets can be cleaned using a solvent available at auto parts stores, followed by a blast of compressed air to blow out the jets. To get even more speed from your moped, buy and install larger jets for the carburetor. Replace old spark plugs with new, high-performance plugs and you will notice additional improvements.
- Most mopeds are designed with long, curved exhausts that perform well over a broad range of revolutions per minute (rpms). Consider installing a new, short and straight sport exhaust system so you can gain the most performance from the higher rpm ranges, where the moped operates when you try to reach top speeds. You can find an example of one of these exhausts in the resources section.
Sprockets and gear ratios
- The sprockets that your moped uses have an impact on the moped's top speed. You may be able to replace the front sprocket with a larger one that has more teeth and get more top speed, but there is a trade-off. You will have less acceleration than before. Rear sprockets can also be replaced, but keep in mind that replacing them has the opposite effect; smaller sprockets would be used for high top-end speeds.