Motorcycle Design and Technology by Gaetano Cocco.
It’s written by an Aprilia employee (most likely an engineer) discussing the science-class aspects of motorcycles. Full color diagrams. Very interesting reading.
Motorcycle Owner’s Manual: A Practical Guide to Keeping Your Motorcycle in Top Condition by Hugo Wilson.
Full-color pictures of the different parts of a bike, and how to perform anything from simple to more complicated maintenance.
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