I have been developing a growing library of airhead electrical system documents. So far I’ve written documents that cover the /5 and /6 1975-76 electrical systems.
For each, I document the wiring system, circuit by circuit, with explanations of what goes where and with notes about well know problems. Another document describes how the electrical components work. I also wrote an Electrical System Basics document to help those who, like I was, are mystified about electricity and how it is applied to our airhead motorcycles.
I’ve been working on these documents off and on for the past two years and figured they might be helpful. You can find them using this link and they are listed on the right hand set of links on most pages.
I hope to add additional documents covering the 1977 RS and possibly the 1983 RS as I have both of those, have completely rebuilt the ’77RS and plan to do the same for ’83 RS soon.
I see more and more questions about electrical system problems, and I expect this to increase as these bikes get older. Many folks struggle with electrical wiring diagrams and don’t have a good understanding of how the electrical components work. So they are at a loss about how to proceed with fault isolation and problem solving. I found that writing this material helped me learn much more about the electrical system and improved by diagnostic capabilities. That’s one reason I wrote these documents; writing things down really helps me learn.
I’ve digested a lot of material others published, among them are Bob Fleischer, Duane Auscherman, Anton Largiader, Tom Cutter and many of the questions and answers that have appeared in the various airhead forums including the micapeak airhead news group and the BMW MOA airhead forum. To all of you, thanks for sharing your knowledge.
I hope this material is helpful. Have a great New Year.
I put together a series of pages about BMW airhead motorcycle electrical systems. It strikes me that electricity in general, and motorcycle electrics in particular, are dark mysteries to many, so I thought I’d shine some light [puns intended 🙂 ].
Lack of understanding hinders confidence when diagnosing and working on electrical projects. As these bikes age, the electrical system is prone to problems as corrosion and neglect makes them behave badly. More owners are having more electrical problems but seem less able to get to the root cause of the problem.
I think one tool that many avoid using is the wiring diagram. The spaghetti of lines, symbols and notations makes the eyes glaze over. “Oh goodness, where do I start?” is the common response to the advice, “Look at the wiring diagram.”
5 Series Wiring Diagram (1970-1973) (Source: Haynes Manual) –> CLICK TO ENLARGE
I’m not an electrical engineer, but I have taken time to learn the basics, have collected comments and input from well respected airhead mechanics and dug into how BMW applied electrical theory when they designed the /5 electrical system. I’ve learned a lot from various reference sources that are scattered about the internet, so my articles include a bibliography of various useful resources. That way both you and I have a nice set of reference materials to consult when problems come up.
I have published three articles (so far), Basics and two about the /5 series: 5 Series Electrical Circuits and, 5 Series Electrical Components. I chose the /5 series to start with because I believe it’s the most popular airhead series for restoration.
I hope to write an Electrical Circuits and Electrical Components document for the /6 and /7 series up to 1984.
Here is the table of contents from the first three documents.