Valve timing diagram of 2 stroke engine?
valve timing diagram of two stroke engine
If the valve timing is correct and there are no damaged engine parts (or weak/faulty valve springs) that should not happen, yet however if the engine is "over-revved" the valves could "float" which is not normal operation. (If the engine is an interference engine there may possibly be engine damage.) That is normal and it is called valve overlap.
Valve overlap occurs in a four-stroke engine at the end of the Exhaust stroke and at the beginning of the Induction stroke; and is when both the exhaust and inlet valves are open at the same time. At the end of the Exhaust stroke, the Exhaust valve is closing and the Inlet valve is starting to open in preparation for the induction of fuel and air into the cylinder. It is common knowledge that in…