What Causes a Motorcycle to Have No Idle Speed?
2 Answers
Motorcycle has no idle speed for the following reasons: Reasons: Inaccurate ignition timing, causing poor idle performance at idle state; Engine has air leakage issues, with damaged connections between the carburetor and the engine; Poor sealing between the spark plug and cylinder head, crankcase, etc.; Faulty spark plug; Blockages in the carburetor's idle jet or air filter, among others. Additional Notes: Motorcycle idle speed (commonly known as small fire) refers to a working condition where the engine runs without load when the motorcycle is stationary. The level of idle speed directly affects the motorcycle's fuel pump volume, and excessively high idle speed can also impact the motorcycle's fuel consumption.
I've been riding motorcycles for over a decade and have encountered idle issues several times. The most common problem is carburetor clogging, especially with older bikes that haven't been ridden for long periods. The gum deposits in the fuel system can block the idle jet. A dirty air filter also affects air intake, causing the mixture to become too lean and the engine to stall directly. When spark plugs are severely carbon-fouled, the insufficient ignition energy makes it hard to maintain stable idle RPM. There was also one time when I adjusted the valve clearance on a cold engine, and the clearance changed after warming up, resulting in valve leakage. For fuel-injected models, you should check if the stepper motor is stuck. My suggestion is to first clean the carburetor and air filter, then inspect the spark plugs. You can do it yourself in about half an hour, while repair shops would charge you at least a hundred bucks.
