Find a book store that carries the English magazine classic bike giude (www.clasicbikeguide.com). There are usually a few drawings of engines with some of the articles on older bikes. The December issue has drawings of a 1967 Norton Atlas engine and a Royal Enfield 1959 Crusader.
A forum community dedicated to Triumph Motorcycle owners and enthusiasts. Come join the discussion about performance, racing, cafe racers, bobbers, riding, modifications, troubleshooting, maintenance, and more!