What are the reasons why a motorcycle can start but doesn't move when accelerating?
2 Answers
The reasons why a motorcycle can start but doesn't move when accelerating are as follows: Automatic centrifugal clutch damage: Improper clutch operation causing it to get stuck without returning to position, resulting in the motorcycle being able to start but not accelerate or move. A broken automatic centrifugal clutch needs replacement or repair. Transmission belt breakage: Usually caused by faults in the pulley or belt, which requires opening the rear transmission system to inspect. If the belt is broken or has significant gaps, it needs replacement. Lean air-fuel mixture: This leads to insufficient gas pressure on the piston after ignition, prolongs combustion time, and causes engine overheating and other faults.
I've encountered this a few times in my decades of motorcycle experience, usually caused by clutch slippage. When you twist the throttle, the engine revs but the wheels don't move—likely due to worn clutch plates or improper adjustment, preventing power transfer to the rear wheel. Another common culprit is a loose or broken chain—once my chain suddenly came off mid-ride, leaving the bike stranded. Throttle cable jams or carburetor blockages, especially during cold winter starts, could also be to blame. First, safely stop and check chain tension and clutch lever free play; if those seem fine, inspect the carburetor or EFI system—faulty sensors on fuel-injected bikes sometimes cause this too. Remember: safety first. Forcing it risks accidents—get a professional mechanic to diagnose it promptly. Regular maintenance prevents major headaches. From my experience, clutch upkeep is paramount—replacing plates costs around ¥100 and solves most issues decisively.
