What is the reason why a motorcycle can start but cannot accelerate?
3 Answers
It is caused by a lean air-fuel mixture or not warming up after starting. If this condition disappears after the engine is warmed up, it should be this situation. High-speed misfire phenomenon: This phenomenon is called high-speed misfire, which means the spark plug does not fire continuously at high RPM, causing high-speed jerking or inability to reach high speed. Solution: Clean the carburetor, adjust the air-fuel mixture to normal, and if necessary, adjust the height of the needle valve. After starting, it is best to fully warm up the engine before riding. This not only avoids this situation but also protects the engine and reduces wear during startup.
I've encountered a similar issue before where the motorcycle engine was running but couldn't accelerate when twisting the throttle. This situation is usually related to several common problems: First, the throttle cable might be stuck or broken, especially on older bikes that haven't been ridden for a long time, causing the lubricant to dry up and making the cable movement less smooth. Another common issue is a clogged carburetor, where dirt buildup blocks the fuel passage, preventing fuel from entering. I recommend first checking the throttle cable for any rust or damage—replacing it with a new one might solve the problem. If the cable isn't the issue, then remove and clean the air filter, as a dirty filter can restrict airflow and disrupt the air-fuel mixture. Sometimes, a faulty fuel pump or impurities in the gasoline can also trigger this problem. It's best to perform regular maintenance, inspecting the fuel system every 500 kilometers to avoid unexpected breakdowns.
Last time my motorcycle had this issue, it started normally but couldn't accelerate when throttling. The diagnosis showed it was a carburetor problem. Specifically, the nozzle or passage inside was blocked by foreign objects, causing insufficient fuel supply. I suspect it might be due to using low-quality gasoline, so I've switched to premium fuel since then. Additionally, spark plug carbon buildup or poor ignition can make the engine struggle to accelerate, which can be improved by cleaning or replacing the spark plugs. I've also noticed that a faulty ECU system can limit throttle response, requiring a diagnostic tool to check the error codes. It's recommended to warm up the bike for a few more minutes before daily rides to keep electronic components stable. Long periods of inactivity can easily lead to this issue, so it's advisable to drain old fuel and clean the fuel system when storing the bike during winter. If you encounter this situation, don't force the ride; send it for repair as soon as possible.
