After a solid introduction to the four strokes — intake, compression, power, and exhaust — students are ready to get their hands dirty and see how all of the components work together. They first identify the major and minor components of the cylinder block, then assemble the internal and external parts such as the piston, crankshaft, camshaft, and flywheel. As the work gets more complex — building the cylinder head, adding a spark plug, mounting the carburetor and fuel tank, installing the muffler and air filter — students become increasingly involved in the intricate and delicate inner workings of the engine.