Why Does the Motorcycle Exhaust Pipe Turn Red?
2 Answers
An excessively rich air-fuel mixture can lead to carbon deposits forming in the combustion chamber, thereby damaging the spark plug. Exhaust Pipe Temperature: The temperature of a motorcycle's exhaust pipe is extremely high. The front section connected to the engine can reach several hundred degrees Celsius, causing water to evaporate instantly upon contact. If the exhaust pipe is removed, flames can sometimes be seen shooting out from the engine's exhaust port. During high-speed riding, the front section of the exhaust pipe may even glow red. Once started, the exhaust pipe heats up very quickly. Exhaust Pipe Maintenance: When starting a cold engine in winter, close the choke to start the engine, and remember to open the choke promptly after the engine warms up. Avoid prolonged high-speed riding with the choke closed. For standard (male-style) motorcycles, do not install windshields or other decorative items in front of the engine and muffler, as this can impede heat dissipation.
I've been riding motorcycles for over ten years and have seen the exhaust pipe glowing red a few times. The main reason is excessively high exhaust temperatures, usually occurring after high-speed operation or prolonged riding. The most common cause is a lean fuel mixture, meaning too much air and too little fuel, leading to inefficient combustion and heat buildup that can't escape. Aging spark plugs causing delayed or incomplete ignition can also generate excess heat, turning the pipe red. If the exhaust system is clogged, such as from carbon buildup or a faulty catalytic converter, heat gets trapped inside and can't dissipate, causing the metal pipe to glow. I remember once after modifying the carburetor and riding at high speed, the entire exhaust pipe turned red. Upon inspection, I found the air-fuel ratio was set too high. I immediately took it for repairs, adjusted the fuel supply, and cleaned the pipes. For regular maintenance, I recommend cleaning the ignition system and checking the fuel injectors to prevent overheating issues. Otherwise, prolonged exposure can cause the exhaust pipe to warp or even crack, which is extremely dangerous if a sudden failure occurs while riding. It's best to have a knowledgeable mechanic inspect it periodically to avoid potential hazards.
