How does a piston move back up the cylinder after the explosion has forced it down?

How does a piston move back up the cylinder after the explosion has forced it down?
The pistons are very much like the pedals on a bicycle. They are attached to a device called a cam shaft that allows the downward thrust of one piston to cause another piston to move back up to be ready to be pushed down again... sort of like pedals on a bicycle. The ignition is timed in a manner that allows the sequential firing of the spark plugs to cause the cam shaft to rotate smoothly. To see what a cam shaft looks like, imagine placing a series o bicycles side by side and welding the pedals of each bike to the pedals of the bikes next to it. Cut off the outter two pedals of the two bikes on the end and what you'll have will be a cam shaft. A piston is attached to each of the welded pair of pedals and the cut off ends are connected to the front wheels in a front wheel drive. There are other components in a real car but that's a high level picture that should help to answer your question. Evan Was Here