What Causes a Motorcycle to Stall When Throttling Down?

[JuliaAnn]

If a scooter stalls when throttling down, it may be caused by an overly rich air-fuel mixture. You can check whether the air filter is oil-soaked or clogged, whether the carburetor's mixture ratio is too rich, or whether the fuel level is too high. Alternatively, immediately reapply the throttle slightly after decelerating from high speed, which usually prevents stalling. Main causes: 1. Unstable idle speed: Stalling when throttling down indicates unstable or excessively low idle speed! If it's too low, it's easy to fix—just adjust it. However, if it's unstable, the issue is more complicated. 2. Prolonged inactivity: If the vehicle hasn't been started for a long time, gasoline can form gum deposits that clog the carburetor's inner walls and jets. Drain the old gasoline and refuel before testing.