The two-stroke engine has been developed to a degree that was not thought possible a few years ago. One of its virtues is that it is mechanically very simple, which is a contributing factor to its widespread use and varied application. Here, engine-tuning expert A. Graham Bell takes the reader through the various modifications that can be made to a two-stroke and its components to give maximum useable power output and mechanical reliability. ‘the words happily avoid textbook syndrome’.