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 recently renamed this site “Brook’s Airhead Garage” in recognition that over the almost 10 years since I started it, 95% of the content is about how to rebuild, restore and care for BMW airhead motorcycles. So what happens? A friend, Rohn, talked me into doing a 72,000 mile service on his 2004 R1150RS.
I too own a 2004 R1150, but mine is an RS. Generally I’ve had a dealer do most of the routine maintenance on it. Although, I have told myself that I ought to broaden my horizons mechanically and become more knowledgeable about it’s maintenance. Rohn’s request pushed me over the edge.
In researching the work required for this service and the history of work done on Rohn’s bike, I noted that his fuel pump is original. Mine died at about 75,000 miles in Des Moines, IA at the intersection of I-35 and I-80 in a construction zone on my way to Michigan. Unlike an airhead, there wasn’t a thing I could do to coax it back to life. I told Rohn he might consider his fuel pump and the internal hoses a “preventative maintenance” item and he agreed to have me replace it.
In looking around for information on the internet, and YouTube, to prepare me for this work, I wasn’t able to find good instructions for replacing the fuel pump. There are several resources that show how to replace the filter, but the fuel pump seemed to be left out.
So, I put this material together to fill that gap.
The first sign of the problem was this bike would not idle well. I thought the carburetors got dirty and all I needed was to clean them. But, before I started on that task, I decided to check the valves and I found the left intake valve lash was 0.012 inches instead of 0.004-0.006 inches. Hmmm …. how did that tappet get so loose?
Before I reset the valve clearance, as I always do, I torqued the cylinder stud and head bolt nuts to 25 Ft/Lbs. But, one stud just spun. Bummer. That means the threads in the engine block are stripped.
It turns out a friend of mine, Dick, had the same problem on his 1972 R75/5 a couple of weeks earlier. I contacted him and learned he made arrangements to rent a jig to repair his stripped threads from Northwoods Airheads. So, we jointly repaired our stripped threads in “Brook’s Airhead Garage” when the jig arrived.
This write-up is based on the work we did on both bikes.
I started this blog back in 2009 as a general blog space with the original name “Motorcycles and Other Musings” to cover the expected content. As is often the case with an idea, it takes it’s own course and becomes what it is meant to be.
This blog is 90% about BMW Airhead motorcycles I’ve worked on in Brook’s Garage which I had built in 2012. SO ….
I changed the name of the blog to better reflect what it has become over the past 10 years.
Same content, same author, same passion for helping amateurs keep their classic BMW airhead motorcycle(s) running smoothly.
I also updated my YouTube channel to use the same name.
I have created over 50 short videos that are used in the documentation of the various rebuilds I have done. The number of subscribers for my YouTube channel is just about the same size as for this blog.
And, I’m starting to plan for another restore/rebuild project soon. The bike is a 1983 R100RS. I may do a “resto-mod” on this bike, or I may not. I’m still thinking about the direction I want to take.
Shortly after I started riding motorcycles, my bike became my only motorized transportation. Consequently, if I had to work on the bike, I had to finish the work or I got to walk. For awhile that work was done on the street by the curb in front of my apartment. It was never much fun, particularly when it was cold and windy.
Any work I did had to be completed “sooner rather than later”. If I hadn’t gotten all the parts I needed to do the work, because something unexpected was really the problem, or I broke something, I had to find a way to get to the dealer. More than once, I put the bike back together, rode to get the part I needed, then rode home, took it apart again and installed the part. The misery of time is nurtured by the need to “be done” and invigorated by having to work in the cold.
Another way to experience the misery of time is when the bike dies in the middle of nowhere. It was a cold Sunday morning on I-10 just past Wilcox, Arizona when the center cylinder of my Kawasaki S2 350 triple seized as I drafted beside a tractor trailer as I tried to get warm. The dead air cut the wind chill by 20 degrees so I could start to feel my fingers again.
A 1972 Kawasaki S2 350 Triple Just Like Mine
I avoided hitting the back of the trailer or going under it when the rear wheel locked up, so that was good. But as the truck receded into the distance, I was on the side of the road with no idea how I was going to get to work 200 miles away in Las Cruces, NM, by noon.
No cell phones in the 1970’s so I had no way to call the manager at Denny’s to alert him of my problem or to call anyone to come trailer the bike. Fortunately, after the engine cooled, the center piston ring broke free when I kick started the bike. I rode on the shoulder of I-10 for a never ending 200 miles to get home. All the while, I listened to every noise the engine made for signs of another impending seizure. This form of time misery is akin to slow, never ending Chinese water torture. Every second seems like a minute.
It took a week for the dealer to get the bike running again, so I walked the 1.5 miles to work and back. Being a starving student, I didn’t know if I could pay the bill, but I got lucky as it only cost $25.00 for a hone and new rings on the center cylinder.
Moving forward about 45 years, I’ve completed three airhead rebuilds so far. The first two took as long as they took with no pressing need to be done. I greatly enjoyed the experience and indulged my curiosity so I could learn what I didn’t know. I could take things apart and reassemble them a second time, if need be, in order to get it right.
I have a heated shop so cold and wind aren’t a factor. When I need parts, I can wait for them to arrive. And I don’t have to walk everywhere until the work is done 🙂 These rebuilds had the luxury of time so they were invigorating and joyful experiences.
But, the last build, a 1977 R100RS, had a deadline. I had no more than one year from the date I started until I had to be done so I could ride the bike to the 40th RS anniversary in Pennsylvania. When I found problems I hadn’t anticipated, which is par for the course, they added to the anxiety as several of them required outside services I didn’t control to do the work for me. Their schedule was not my schedule.
A Shake Down Ride to the Coffee Shop on My Last Build, 1977 R100RS
I made the deadline, but in all honesty, for much of that build, the work was not very joyful. Many times that year, I had an old, uncomfortable feeling I couldn’t put my finger on. Then it dawned on me. I inadvertently invited the misery of time to come join me in the shop as soon as I set the deadline.
This is a good reminder to me to let the work proceed at it’s own pace and not worry about hitting a deadline. This is how you train time to become a joyful luxury instead of a misery.