What Causes a Motorcycle to Emit Blue Smoke?
1 Answers
Blue smoke from a motorcycle is caused by factors such as incorrect engine oil viscosity selection, carbon buildup on piston rings, and aging valve stem seals. The specific reasons are as follows: Incorrect Engine Oil Selection: Manifested by no blue smoke during cold starts in the morning, but slight blue smoke emission after the engine warms up. Previously no blue smoke was observed, but it appears after switching to a different type of engine oil. The motorcycle maintains acceleration capability, but engine oil consumption becomes excessive, and engine noise increases. Carbon Buildup on Piston Rings: Carbon deposits cause the piston rings to lose tension, resulting in poor sealing. Engine oil enters the combustion chamber through the gaps. This leads to reduced power, decreased cylinder compression sealing performance, and relatively increased engine oil consumption. Aging Valve Stem Seals: Hardened valve stem seals fail to expand and contract with temperature changes during engine operation, allowing engine oil to enter the combustion chamber during cold starts. A stuck PCV valve permits combustible mixture to leak into the crankcase, causing the engine oil to deteriorate and thin, thereby accelerating its consumption in the combustion chamber.