The great news is that this classic is back in print, online, for free, and you can get it here:

Owner's Guide to the Dual Plug Ignition System
by Tom Cutter
(131k Acrobat file) Download Now!

For those who have a dual-plugged airhead, or those who have ever thought about it, this is a classic reference on how this modification is done, and most importantly, how to tune the bike correctly with dual plugs installed.

Yes Dorothy, we're not in Kansas any more- that combustion front takes a whole lot less time to get through the cylinder. And how can you take advantage of dual-plugging's tolerance for leaner fuel mixtures without blowing it up?

Detailed instructions are given, along with profuse charts listing correct applications for each engine size. Wiring diagrams for the ignition system are included, as well as diagrams for modifying the points plate. Detailed carb jetting instructions are included, with jet numbers.

Tom comments:
I thank Ken and Paul for their recent efforts to bring this
HISTORICAL document online, I have to stress that the Dual Plug Guide is factually
INACCURATE in many ways. It was, to the best of my knowledge, accurate when
it was written 23 years ago. It is no longer so. We have made many advances in
dual-plugging technology, and many of the sources listed in that book are long
since out of business or moved. Many of the products referenced are no longer
available, and others have had part numbers changed. Even ignition timing
recommendations are out-of-date, as we now have better fuel available to us, as
well as unleaded-fuel-compatible valve components, which render some of the
advice obsolete.

The purpose of putting it online was for collectors of older BMW's to
have a source of a "period-correct" Guide.

PLEASE do NOT email me with questions and arguments about the facts
contained in the Guide. They are INCORRECT and OBSOLETE. Further, do not mail or
ship anything to the address shown under my name on page 1, as I haven't
lived at that address for over 20 years.

Tom Cutter

Author Tom Cutter is well known among airhead lovers online through his extensive work at the World Renowned Rubber Chicken Racing Garage, in Yardley, PA, for dispensing limitless amounts of useful advice based on his years of experience as a mechanic, dealer, and hands-on guy, including time at Butler & Smith, BMW's importer to the US before the days of BMWNA.

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