For example, when cleaning carbon deposits by the soaking method, the cleaning fluid is not cleaned up, causing the Mitsubishi Engine to top the cylinder when restarting; for Bare Engine equipped with a variable intake duct system.

If the cleaning agent flow rate is not properly matched with the speed of the Mitsubishi Engine, it may cause excessive cleaning agent to accumulate in the intake manifold, and the intake port becomes a short intake port when driving at high speed. The cleaning agent in the intake manifold is instantly sucked into the combustion chamber, causing the top cylinder.

After the rollover, the oil in the oil pan flows into the air filter, intake manifold and intake port through the universal pipe of the crankcase.

After the Mitsubishi Engine is started, a large amount of oil is sucked into the combustion chamber. During the compression process of the piston, the pressure on the top of the piston increases because the oil cannot be compressed, and the connecting rod bends and deforms.

After the user's long-term driving, the connecting rod suddenly fatigues and breaks at high speed. It can be judged whether there is oil in the air filter by investigating whether there is a rollover accident record, and abnormal traces of piston ring height.

The crankcase system is damaged and causes the oil to top the cylinder, causing the connecting rod to bend or break. For Bare Engine equipped with a variable intake system.

If the ventilation valve of the diaphragm crankcase is broken, a large amount of oil may be continuously sucked into the intake manifold and gradually accumulate. When driving at high speed, the intake port becomes a short intake port, and the oil in the intake manifold is instantly sucked into the combustion chamber, causing the cylinder to top.