Go Kart Engine Building: The Yamaha J - written by Australian author David Hogan.

This book shows in pictures and describes in detail the building of a late model standard J engine which had been raced at two meetings and when measured on a dynamometer produced 7.4hp. The same engine after being prepared for racing according to the blueprinting procedures covered in this book produced 9.8hp. A further increase in power could have been achieved by changing the transistor ignition for an early model CDI ignition. The procedures to achieve the increase in performance are simple, commonsense and well proven over time. The power readings were taken by the same operators on the same dynamometer and while the actual horsepower numbers may vary from dyno to dyno the percentage increase in horsepower will remain the same. While this book is specifically about theYamaha J engine good results can be obtained if the procedures outlined in this book are applied to the Yamaha KT 100 S engine. The more powerful S engine has a different bore and stroke to the J engine and has different port dimensions and shapes however both engines are still single cylinder, piston ported, air cooled two stroke kart engines. The Yamaha J and S engines both use the Walbro carburetor and the exhaust systems are very similar.