TECHLINE Donny’s Technical Guide Book

There are two primary ways to become skilled at bike wrenching: go to tech school or learn on your own. The amount of available material is infinite, and it could take a lifetime to sort the good from the not so good, if you choose the latter route. Thankfully, however, there is one printed resource that has distilled valuable information into an easy-to-read, easy-to-learn format: Donny’s Unauthorized Guide to Harley-Davidson 1936 to Present, Volume II: Performancing the Twin Cam. The follow-up to Donny Petersen’s immensely popular Volume I, the new book is a remarkable collection of technical expertise, mechanical tips, and detailed explanations of everything Twin Cam related. AIM readers are intimately familiar with Donny from his monthly Techline column, and Volume II is similarly insightful and informative, but with several hundred pages to indulge in.

Covering topics from oil coolers to vibration to horsepower, Donny takes readers on an amazing journey though Twin Cam land, employing precision and clarity, while sharing his words and wisdom with ease. The text is accompanied by photos and diagrams to complement every subject, so readers can go step by step without getting overwhelmed. Whether your goal is to gain a substantial amount of new mechanical understanding, or simply augment your present knowledge base, Volume II will assuredly become the most important tool in your possession. And for a relatively minor investment, (hardcover $49.95; softcover “Garage Copy” $56.95), Donny’s newest technical tome is the soundest economic decision you can make to learn all you want about H-D Twin Cam powerplants.

Donny’s Unauthorized Guide to Harley-Davidson 1936 to Present, Volume II: Performancing the Twin Cam is a rare publication in that it is produced by a true expert in his field. And if you enjoy reading Donny Petersen every month here in American Iron Magazine, you’re guaranteed to love his new Volume II. Buy it, read it, wrench it … it’s that simple! AIM

–Adam Williams as published in American Iron Magazine, the world’s best selling Harley magazine.