Darryl's Blog
A Pedantic Rant About "Star Frame" BMWs
The topic for today's rant is the Pressed Steel Frame bikes that BMW produced between 1929 and 1941 or so. Actually, it's not about them at all, but rather, the English language nomenclature surrounding them.
Quick history: BMW started making bikes in 1923 with the introduction of the R32. This bike, and the the succeeding two generations up to the R52/R57/R62/R63 in 1929 had a double cradle frame constructed from steel tubing that was brazed together with lugs. Compared to many manufacturers that were making scaled up bicycle frames for their motorcycles, BMW's "tube frame" (Rohrrahmen in German) or "hanging tank" (Stecktank) bikes were strong and stiff, and other than the undamped leaf spring, trailing link forks, gave good riding feel. But the brazing wasn't strong enough to deal with heavy sidecar loads, and gained a reputation for cracking.
BMW responded with the R11/R16 in 1929. A year previously, the company had acquired the Dixi automobile company, located in Eisenach, and had entered automobile production. Along with the factory came heavy stamping equipment, and BMW's engineers saw a way to eliminate the weakness of the tube frame bikes. The new bikes came with twin C channel frame loops that were rivetted together. The construction looked very heavy and the resemblance to a bridge was unmistakeable. In spite of the looks, the frame was quite lightweight. And it could stand up to nearly any abuse. Even when it was pushed beyond the failure point, it failed gracefully, bending and bowing rather than cracking and breaking.
Now, to the rant. These bikes have come to be known in English as Star Frame bikes. Anyone admiring one of these frames would be hard pressed (sorry) to understand how they could look anything like a "star". They simply don't. They look like they should be part of a bulkhead in a battleship. There is nothing polygonal or pointy about them.
The earliest reference I can find to a Star Frame is in the wonderful book Bahnstormer, by the late L. J. K. Setright. This book, published in 1977 and long out of print, presents the BMW motorcycle story from the standpoint of a particularly interesting and opinionated auto and motorcycle journalist. The prose is beautiful and tells you almost as much about Setright as about BMW, with his journalistic interest in racing and corporate doings. Setright explains about the introduction of the pressed steel frame bikes:
Such was the background to the introdution in 1929 of the pressed steel frame in the new R11 and R16 motorcycles from Munich. It was known colloquially as the Star frame, and its most notable feature was the broad and generous gussetting that supported the steering head and embraced the newly curvaceous petrol tank. Equally neat and similarly superior frame engineering could be ssen where the final drive bevel box and hub were fitted into the pressed steel loops at the rear of the chassis, and in the elegant beams that constituted the front forks, still bearing trailing bottom-link and leaf-spring suspension.
Emphasis mine.
Setright doesn't elaborate where he found this colloquialism. Many writers in English subsequently have used the term. However, in German, a star frame would be constructed as Sternrahmen. So far as I can tell, the Germans never use that term for these frames. BMW's own publication, BMW Profiles: Motorcycles from Munich 1923-1969 does not use the term. The German language book, BMW Motorräder 1923-1969 by Stegmann and Vennekate, for example, simply uses the same words (pressed together, as is the German wont): Preßstahlrahmen.
So, where did this Star Frame come from? I believe that it results from a misunderstanding by the otherwise erudite Setright. All BMWs of this era, up until the introduction of the plunger framed R51 in 1938, were hard tail bikes, sans rear suspension. In German, such a rigid frame bike would be called a Starrrahmen. Starr, with the trailing double R, means rigid in German. But this term would apply equally to the preceding tube framed bikes, and in fact, nearly all of the motorcycle production in the world at this time. It's not a distinguishing factor.
The confusion is easy to understand. A source or a table, might list that the R11 had a Starrrahmen and it turned into a Star frame. Easy to understand, but a mistake to repeat, and distracting from the subject matter.
BMW's Schizoid Motorcycle Riders
So, I was chatting with Ted Porter last week and we got on a subject that apparently drives him as wild as it does me. So I thought I'd address it here:
This has to do with BMW and how people perceive them with regards to their Airhead or Vintage BMW bikes.
BMW as Devil
If you've ever been in the presence of a group of strident Airhead Beemer Club members, you know a couple things: there has never been, and never will be again, a better bike; and, BMW is conspiring to do anything at all that will make the Airhead's life more difficult and expensive, and to shorten the working life of the airhead bikes.
BMW tried to kill off the airheads, not once, but twice. The first time was when they brought out those water cooled, inline four K Bikes that are nearly Japanese in layout, styling and character (or lack of it). When that didn't work, they designed the "New Boxer" which has come to be known as the oilhead (for its second oil pump dedicated to moving a cooling flow of oil around the exhaust valve area in the head, and, at the same time, caused the post hoc creation of the airhead moniker). This was equipped with electronic engine management, ABS brakes and other incomprehensable things that make it essentially impossible to work on if something should fail and expensive to buy parts.
BMW has gradually been removing support for airhead bikes. Most shops don't stock regular parts and won't work on airheads. Even some of the better shops have stopped taking "points bikes". The owners, no matter how removed from actual wrenching, are becoming more knowledgable and able to effect maintenance and repairs than the dealers, whose mechanics know less and less about them.
So it's a very good thing that these bikes, designed back before BMW was ruled by the bean counters, are extremely maintenance friendly. Unfortunately, BMW keeps on jacking up the prices of the parts. And while the prices of maintenance items like filters have gone up, the cost of replacement parts has skyrocketed! In fact, even simple nuts and bolts recently took a big jump!
BMW as Angel
First of all, the very newest airhead bikes are pushing 15 years old. Have you tried going into a dealership for any other motorcycle brand and asking for parts for a 15 year old model, let alone one that is almost 40 years old? They can't remember that far back. These bikes are truly becoming vintage vehicles.
Even if a dealer doesn't have the part you need in stock, they can order nearly anything. If you are travelling and your airhead develops a problem, any dealer should be able to "VOR" (vehicle off road) the part for a surprisingly small surcharge and, if it's in the US, get it the next day.
BMW, at least as of a couple years ago, still offered a 2 day factory school covering airheads. Why would they do that? You may well say that a mechanic can't learn all that there is to know about an airhead in 2 weeks, let alone two days — and that is true. But none of the other manufacturers is offering classes for anything but their very newest models. BMW is going far out of their way to continue to support their older models.
The reason why dealers don't want to take on airhead jobs, even just routine maintenance, may have little to do with training anyway. Older bikes, even those that are well maintained, can have "issues". This is highly compounded for bikes with less than a perfect provenance. A typical airhead bike has a market value in the $2500 - $6000 range, depending on the model and condition, of course. Especially at the lower end, it's easy to start finding problems that, if repaired, will swamp the value of the bike. Things like warped rotors, worn transmission input splines and wheel hub splines, stripped header nut threads and so on are multiple hundred dollar problems. A dealer won't find these until they are in the middle of a "tune up", and it may not be safe to put it back together as is. And when the dealer calls the owner and says that the $300 estimate just ballooned to $2000, the dealer may end up stuck with the bike.
As far as the expense of parts goes, today a US dollar is worth 70 euro cents. Even eight years ago, the greenback was worth €1.18 — it's only worth 3/5ths what it once was. In addition, the parts for the older bikes must be stored somewhere, and that costs money, too. You're not just buying new harvest beaujelais here, but 25 year old vintage port.
In other words, the parts and supply is only available because BMW does care about these old bikes, even though they do not stand to make much money from them ever again.
Postscript
Of course, the real truth is somewhere in between. BMW stands to burnish their reputation for solid products and support by putting in the effort they do. The word of mouth value is worth a lot more than what can be bought with advertising. And perhaps someone with an old bike will, themselves, occasionally buy a new one, too.
BMW is a for-profit company that must answer to its shareholders. They are not a charity that exists to support old bikes. The fact that they somehow feel that parts availability for 40 year old models is worthwhile is pretty much astounding. If there are some parts that have been superseded or are simply NLA, it's not really that big a surprise, is it?
A Sudden Spurt of Progress
This title applies to two things going on at the moment. The first is this web site.
My website had grown by accretion from 2001 through 2009. Other than having a few templates via Adobe Dreamweaver (which is a pretty darn good integrated web development environment), some barely integrated JAlbum photo albums (another extremely easy and creative tool to use) and some custom PHP and Javascript scripts, it was all hand coded.
I admit that keeping it up to date was tedious. In fact, I never really filled out all of the pages I had initially envisioned.
Maybe a year and a half ago I got introduced to Mambo, an Open Source Content Management System (CMS). I played with it a bit, but frankly, even after buying a (useless) book (that merely reiterated all of the menu options), I couldn't really make heads nor tails of it. Shortly after that, though, I found the Drupal CMS. Drupal (which sounds like the Dutch word for droplet, and hence its logo) was far more intuitive for me, and after learning a bit more about it, I've done several projects with it.
Now I am bringing it to my own website.
What's cool about a CMS is that you don't have to have the keys to the kingdom to work on it. Once it's set up, nearly everything can be done with just a web browser. I still have to do a bit of hand coding to get phrases hyperlinked and put italics and bold text inline, and to include photos in blog pages like this, but that's really pretty trivial.
I spent several weeks playing around to get the basic look the way I wanted it. Now I'm just filling out content. Some of it is stuff I'm moving over from my old site; and some of it, like this blog, is entirely new.
The other thing I'm working on and finally! am making some progress again is my 1941 BMW R12. It has been sitting idle, waiting for this and that, while I am generally riding around on my other bikes.
This past January, my friend Brian from Seattle came down with the transmission. He had rebuilt it, but he couldn't, by himself, put it back together. The main reason for this is that the kickstarter must be held in a particular position during assembly. Between he and I, we were able (just barely) to hold it against its spring, get the other three shafts installed and lined up on the rear cover, heat the case, and put it all together.
Unfortunately, when I installed the transmission in the bike, I found that the kickstarter was completely locked. I looked in through the opening for the hand shifter, I poked and I prodded, but the kicker was stuck good.
I knew it had to come apart, but I dreaded it. So, I did what I do so well — I ignored it. Unfortunately, that didn't help. So, a week ago, I took it apart again.
I'm not sure, but I think the problem was the ratchet. Although there are only a few pieces that comprise the kicker, they work in a subtle fashion. In this case, I think that when we put it together, we got the ratchet set right on the edge of the disabler mechanism, which allows the transmission to spin without clicking the ratchet. And I think that, while I was struggling to install the transmission into the bike, using the lever (among other things) for leverage, it got jammed just at the edge of the range.
After setting it up again and spending a lot of time wondering how I was going to build some special jig to simulate three hands holding everything just so, I realized that I could remove the top screw from the kickstarter bushing and put a pin — just the right thickness pin — into the hole, and it would hold the kick lever in just the right way. Reassembly was suddenly a snap.
Good thing, too. Because about the last thing you do, after putting the main parts together, is install the shifter forks and then thread the shaft that aligns them through the case and the back cover. Each fork has a recess for a spring and a ball bearing, and the shaft has a set of detents on each side. When shifting, the balls go into the detents to align the forks in the right position for each gear. It's wonderfully simple.
Except. To put this together, one must push the ball against the spring into the recess, then tap the shaft up to that point and over, to trap the ball. If one should happen to lose control of the ball or not get the shaft entirely over the ball, that ball either shoots out of the case and hits you in the face (yet another good reason to wear safety glasses!), or it falls to the bottom of the transmission and rolls immediately to the lowest place, which is under the kickstarter ratchet gear.
It turns out that there's actually not quite enough clearance between the gear and the bottom of the case for the ball to roll under. Instead, it tends to get trapped.
Six times it got trapped. And six times I had to open the transmission again and close it up again. I am so inept.
Anyway, I finally did the deed and it is now snugged up against the motor in the frame.
I have spent the last few days constructing a custom wiring harness for the bike out of cloth covered wiring. I just installed the horn today.
Now I've got to get the painted pieces back from Danny Irby.
A Funny Thing Happened On The Way Out The Door...
I had an odd thing happen a couple weeks ago. I jumped on my 1953 BMW R51/3 to go visit a guest in town over at a friend's house. I fired it up — first kick start, just like usual — and rode down the hill. But as I tried to use more throttle going up the incline towards the back exit from my home, I found that the engine seemed to be missing about about 3/8's throttle. I turned around and rode back home, struggling up the steep road to my house.
I had no time to look at it later that week. I put it on the lift and ignored it for a few days. This often seems to be the best technique for fixing things. Having no real brainstorms, I took off the front cover and verified that there was no arcing across the points (could be a sign of a dying condensor), no sparks jumping the safety gap on the magneto (bad plugs, caps or high tension leads), and that the centrigual advance weights seemed to be moving appropriately.
I also thought it might be a fuel starvation issue, so I checked the screen in the petcock bowl and checked the fuel flow rate. The screen was clean and I seemed to be getting at least 1/3 liter of gas/minute out the fuel lines.
So, I left the bike up on the lift for a few more days. It seemed I was going to have to go in deeper to solve this mystery. Although I didn't have a good reason for thinking so, it seemed that it was more like fuel than ignition. I leaned over the left carb, thinking about how annoying it was going to be to take it apart and clean it. Maybe there was some water in them.
As I was leaning over, my eye momentarily wandered to the air cleaner. There it rested — there was something odd about it. I gave it more attention and realized that the choke lever, which I never touch because the bike doesn't need it and BMW's manual recommends only using it when the temperature is below freezing, was completely closed.
About 4 weeks ago I had my annual Tech Day here. I can't say for sure, but it may be that someone closed the slide then. I'm not sure I've ridden the bike since then. I love having the event and getting people interested in old bikes. Perhaps someone didn't know what that lever did, although it's definitely a generational thing: I've never owned a car that had a choke, but when I related this to my mom, she instantly said that those symptoms matched a closed choke.
Anyway, I quickly checked the choke on the R60/2, just to make sure.
