It does not hurt an engine to run it with no exhaust muffler
you may burn up the exhaust valve.i would not do it.
If you run the engine without pipes , you will inevitably start a fire under the hood from the flames shooting out of the exhaust ports
No, not really. An engine will run without an exhaust (but you may get arrested). The exhaust simply directs waste gasses and quietens the noise. It plays no part in the running of the engine, but can reduce the performance if it causes on obstruction to the gasses.
Yes. A car can run without an exhaust manifold. It will burn out the exhaust valves in the cylinders a lot faster than normal, but it can be done.
Your engine is most likely overfilled with oil. Check your oil and make sure it isn't overfilled. However a little oil coming out the exhaust isn't gonna hurt anything, your just gonna waste a heak of a lot of oil
Does it hurt the engine? Yes and no. It won't hurt to run the engine for a while. But running without a fan shroud seriously reduces the efficiency of the cooling system. Consider the shroud on a rad as a type of straw. Without it you won't suck much air through the rad. At slower speeds this will probably end up as an overheat situation. If the vehicle came with one, use it.
No, exhaust does not have enough oxygen in it for the engine to run.
A dual exhaust system is designed to reduce exhaust backpressure, making the engine run more efficiently.
Without the exhaust back pressure, the engine could run a little richer. You may need to readjust the carbs to get the bike to run smoother.
You can run an engine in/out of a car without a transmission. Car wont move and engine wont be mounted properly. So i suggest not to run an engine without a transmission unless you know what you are doing.
running 40:1 in a 50:1 engine will not hurt anything. all you are doing is running more oil in the fuel so will be getting more lubrication as well as more smoke out the exhaust.