Why is the EFI motorcycle idle unstable?

[LucilleLynn]

The reasons for unstable idle speed in EFI motorcycles are as follows: 1. Throttle carbon buildup blocking the air passage: Carbon buildup on the throttle can affect its opening degree and the intake air volume, causing the engine speed to fluctuate between high and low when starting the motorcycle cold, resulting in instability accompanied by shaking. If the throttle is too dirty, it needs to be cleaned. Generally, cleaning can resolve the idle instability issue. 2. Low fuel pressure or intake manifold leakage: For example, clogged fuel injectors or fuel lines, insufficient fuel pump pressure, or faulty fuel pressure regulators. This leads to poor atomization, an abnormal air-fuel mixture ratio, incomplete combustion, and unstable idle speed. If there is an intake manifold leak, it can affect the accuracy of the intake pressure sensor's feedback data, causing the ECU to inaccurately control the intake air volume, resulting in an abnormal air-fuel mixture and unstable engine idle speed.