If you have checked the fuel system, rollers, and driving belt on your 50cc moped and it is still experiencing issues, there are a few other potential causes you may want to consider:
Spark Plug: A faulty or worn-out spark plug can cause poor ignition and result in the engine dying while riding. Check the spark plug for signs of wear, such as fouling or excessive carbon buildup. If necessary, clean or replace the spark plug.
Carburetor: The carburetor plays a crucial role in mixing fuel and air for combustion. If the carburetor is dirty, clogged, or misadjusted, it can lead to fuel delivery issues and cause the engine to stall. Consider cleaning or having the carburetor professionally serviced.
Air Filter: A clogged or dirty air filter can restrict airflow to the engine, leading to poor performance and stalling. Inspect the air filter and clean or replace it if necessary.
Electrical Issues: Electrical problems, such as a faulty ignition switch, wiring, or a failing charging system, can cause intermittent power loss and result in the engine dying. Check the electrical connections, wiring, and components to ensure they are functioning correctly.
Engine Compression: If the engine's compression is low, it can cause performance issues and stalling. Consider performing a compression test to check the health of the engine.
Fuel Quality: Ensure that you are using clean and fresh fuel in your moped. Old or contaminated fuel can cause running issues. Drain the fuel tank and carburetor if necessary and refill with fresh fuel.
If you have attempted these troubleshooting steps and the issue persists, it might be best to consult a professional mechanic or take your moped to a reputable service center for a thorough diagnosis and repair. They will have the expertise and specialized tools to identify and resolve the specific issue with your moped.