What Causes Fuel Cut-off in EFI Motorcycles?
2 Answers
The reasons for fuel cut-off in motorcycles are as follows: Fuel supply system failure: If the motorcycle gradually slows down while riding, the engine slowly shuts off automatically, and there is a noticeable lack of power before shutdown, it is generally a fuel supply system issue. In this case, check whether the fuel in the tank is exhausted. If there is sufficient fuel, check whether the fuel switch is turned on. Cylinder head gasket damage: If the engine makes a loud "popping" sound during shutdown and cannot be restarted afterward, and the kick starter feels very weak in compression, it can be determined that the cylinder head gasket has been burned through or the crankshaft oil seal is damaged. Remove the valve cover for inspection. If the cylinder head gasket is damaged, replace it with a new one. Oil seal damage: If the cylinder head gasket shows no signs of damage, check whether the crankshaft oil seal is damaged. Remove the parts outside the crankshaft oil seal and take out the oil seal for inspection. If the oil seal is damaged, replace it with a new one.
I often encounter this issue in repair work. Fuel injection motorcycles cutting off fuel supply is mostly due to problems with the fuel pump, such as internal motor wear or poor contact in the fuel pump circuit, leading to an inability to pump fuel. It could also be caused by a clogged fuel filter, where accumulated impurities block the fuel line, especially common after long-distance rides. Sometimes, the ECU control unit misinterprets sensor data, such as faults in the oxygen sensor or throttle position sensor, and actively cuts off fuel to protect the engine. I recommend that owners first check if the fuel level is sufficient, then listen for a humming sound from the fuel pump when starting; if there's no sound, it might be a blown fuse. Regularly replacing the fuel filter and using high-quality gasoline can effectively prevent this issue—don't wait until the engine stalls mid-ride to check. If fuel supply is cut off, it's best to seek timely repairs and avoid tampering on your own to prevent damaging the circuits.
