This classic has been completely updated for the second edition. John Robinson, the Technical Editor of Performance Bikes', explains how various stages of engine tune are reached, and describes typical development work with enough theory to devise a practical development programme. The phenomena described are all known to work - the trick is making them all work together. Engine development is slow and expensive, but the results can be very rewarding, both in competition and in the sheer pleasure of using a motor which is crisp and perfectly set up. Although it is not possible to make all-round engine improvements, other than those gained by careful assembly to the exact stock tolerances, improvements in one area can be traded' for losses in another: increases in high-speed power balanced perhaps against losses in low-speed power, engine flexibility and reliability. John Robinson takes the reader through the processes which are necessary to make your four-stroke run perfectly. Will be promoted by PERFORMANCE BIKES