Will water in the motorcycle exhaust pipe enter the engine?

[MacBeckett]

Water in the exhaust pipe cannot enter the engine. When the engine is off, the valves are closed, and only the exhaust pipe will be filled with water. After starting and driving a few kilometers, the water in the exhaust pipe will be expelled, and any remaining water will evaporate due to the high temperature. Here is more information about motorcycle engines: 1. Concept: A motorcycle engine converts the thermal energy generated by igniting the fuel-air mixture in the cylinder into mechanical energy, which is then transmitted to the rear wheel through the crankshaft and transmission mechanism to provide driving power. 2. Advantages: Motorcycle engines have the advantages of low inertia force, minimal vibration, and low noise.

[MacAlan]

I've been riding motorcycles on long-distance trips for over a decade and have experienced exhaust pipe water intake several times. During normal rainy days with shallow puddles, water flowing along the exhaust pipe walls isn't an issue because the exhaust valve closes after engine shutdown, preventing water from entering the cylinder. However, once when I stalled in deep water and curiously tried restarting the engine, it just made a clicking noise before seizing completely. Later disassembly revealed the cylinder was full of water – the piston sucked water in during downward movement, then hydraulic locked and bent the connecting rod during compression. Now I'm extra cautious in rain: I always check water depth before crossing, and absolutely detour if it exceeds exhaust pipe height. If stalled, I push the bike to dry ground and wait half a day, only attempting ignition after confirming no moisture at drainage holes. This lesson isn't worth repeating – engine replacements are prohibitively expensive.

[VanJade]

I've seen quite a few waterlogged motorcycles while working at the auto repair shop. Water entering the exhaust pipe doesn't necessarily mean it will reach the engine—the key factor is whether the engine was running. When the engine is operating, the exhaust pressure can push water outward. However, if the engine stalls, water trapped in the exhaust pipe becomes dangerous. Last week, a young guy restarted his bike immediately after stalling in water, causing water to backflow from the exhaust into the cylinders. When we disassembled it, we found the piston rings were deformed. Motorcycle exhaust pipes are designed with bends and drainage holes to block most rainwater, but if the entire bike is submerged in deep water, even if the air filter isn't flooded, water can still be sucked into the cylinders due to the siphon effect. That's why shops recommend removing the spark plugs to drain water first after submersion—don't cut corners by trying to start the engine directly.

[JaxonLee]

Last month, I was riding my bike home when I encountered a heavy rainstorm. The exhaust pipe got filled with water, and then the engine started making strange noises. I rushed it to the repair shop, and the mechanic said I was lucky that water didn't enter the engine. He explained that motorcycle exhaust systems have curved structures, so when parked, water accumulates in the muffler. The exhaust pipe is usually positioned lower than the engine valves, making it difficult for water to flow back into the engine. However, if the bike stalls in deep water and you try to restart it immediately, the piston movement might suck in water. That time, the mechanic advised me to avoid waterlogged areas when riding in the rain. If the bike does stall in water, I should first get help to lift the bike out of the water and let it dry. Now, every time I see a puddle, I get nervous—the repair costs could cover half a year's worth of fuel!