What Causes a Motorcycle to Lose Power When Accelerating?

[DelRafael]

Motorcycle losing power during acceleration is primarily caused by carburetor blockage, improper air-fuel mixture, excessively small valve clearance, or fuel shortage. Below are more detailed explanations: Carburetor blockage: If the idle jet is clogged, the motorcycle will have no idle speed; if the main jet is blocked, it will exhibit poor acceleration at high speeds, commonly referred to as "losing power." This issue can typically be resolved by removing and cleaning the carburetor. Improper air-fuel mixture: An incorrect mixture ratio can lead to unstable idle speed and a sensation of power loss. This is relatively easy to fix—simply adjust the idle screw until the idle stabilizes. Excessively small valve clearance: For most standard motorcycles, valve clearance ranges between 0.05-0.12mm, varying by manufacturer and model. To check valve clearance, remove the valve cover or cylinder head cover, align the timing, and inspect the clearance. Alternatively, if the rocker arm feels very tight with no play when moved by hand, the clearance is too small. Fuel shortage: Check if the fuel tank is empty.