These pages are taken from A guide to OS model 4 strokes by Grahm Rice and the book was sold through the RCM anthology library series. If you look up RC Modeler magazine they may still have this little book listed. It is old but for someone new to 4 strokes it is worth it's weight in gold. I bought this one years ago when I started rebuilding my own engines, it's step by step, some thngs have changed but not a lot so it still works today. Print it out so you can read it and tack it to your wall!!