Mon, 08/30/2010 - 19:39
Hi All this is my first post here, ive been lurking but thats it. Any way I wanted to introduce my self Im a school teacher in upstate NY and I build motorcycles with a small group of HS kids as a club niskygarage.logical.net is the web site the kids built and maintain you can check out our projects. Any way I have had a bug in my ear for a long time to build a vintage project with the kids. I would love to introduce the kids to somthing classic. So my question to you all is how user friendly are the old bmw's?? are the parts easy to come up with?? which model would you all suggest? also is their models I should stay away from? Im sure Im going to ask a ton more questions but this is a great start! let me know what you think of the projects!
Thanks a bunch in advance
RichieD
- 551 reads
Mon, 08/30/2010 - 21:31
#2
That's a pretty good
That's a pretty good summary...people should bookmark that post!
Other places to read about BMW motorcycles might be some of the various Wikipedia entries...mostly contains good information:
http://en.wikipedia.org/wiki/History_of_BMW_motorcycles
http://en.wikipedia.org/wiki/Airhead_%28motorcycle%29
Look at some of the models listed at the bottom of the first link and follow that to other pages for specifics about those models.
Tue, 08/31/2010 - 08:38
#3
That is a great start for me
That is a great start for me thank you! I did see some folks building cool cafe style bikes out of a PD?? Im not sure what that was but they did cut the heck out of the frame and make it look much more sparce than it originally was. Could anyone explain what PD is? sorry of my ignorance on this one.
Tue, 08/31/2010 - 09:25
#4
GSes and PDs
The R80G/S was introduced in 1981 and is BMW's "dual sport" model. By this, they have always meant, a street bike with some offroad capabilities. While BMW has won about 5 Paris Dakar races (the PD in the GS-PD name), these are not real dirt bikes.
I didn't mention the GS line because they tend to go for more money in the used market, and the original R80G/Ses are starting to become collectible.
The R80G/S (gelände/strasse in German, or off-road/on-road) intorduced the monolever single sided swingarm. In 1988, I think, the R100GS (no slash) came out with the paralever single sided swingarm. This is an extra linkage from the final drive case to the frame, and it prevents "shaft jacking", or the tendency for the bike to rise on its rear suspension under acceleration and fall under decelration (an effect that occurs on shaft drive bikes because the pinion gear tries to climb up the ring gear under power). The paralever spread to BMW's K bikes and the "Oilhead" boxers that were introduced in 1994, but was not on any other Airhead bike.
However, the paralever GS Airheads have a poor reputation for longevity of the driveshaft. The paralever design includes two U-joints, and apparently because of the extreme angles that are possible at these joints, especially if the bike is loaded down, some seem to find that they only last 20-30,000 miles. They are not intended to be maintained, although there is someone out there marketing a replacement with zerks built in.
Tue, 08/31/2010 - 09:36
#5
To my eye, the /5s and /6s
To my eye, the /5s and /6s make the best candidates for a cafe bike. You can almost see it in this stock /5 bike with a solo seat:
Tue, 08/31/2010 - 09:50
#6
Make sure you know what
Make sure you know what you're doing when you do frame modifications, etc. I give the BMW engineers credit for figuring this stuff out, getting the rake/trail correct, wheelbase, height, tire sizes, etc. If you deviate too much from this baseline, there's no real guarantee what you're going to end up with and someone could get hurt.
There are people who are experts at frame geometry and design. Tony Foale is one name that comes to mind. He has a website somewhere out there...probably http://www.tonyfoale.com or something very similar.
Wed, 09/01/2010 - 20:07
#7
I saw this site
I saw this site http://www.teamincomplete.com/Boxer/boxerhome.html
I see that it is a 92 frame they modified here I also think they used a 92 motor and drivetrain? but I get confused with the bike he tossed with the tank slapper. anyway that would be fun to build but any shots from the peanut gallery would be appricated
Thanks in advance
RichieD
Thu, 09/02/2010 - 00:54
#8
Here's another frame
Here's another frame modification project that I'm aware of:
http://www.rockerboxer.com/project.html
Another beautifully done cafe'd R90S is by Jon-Lars Sorenson. He might be on Facebook. Here's a link to an on-line photo gallery:
http://www.kodakgallery.com/I.jsp?c=e0gbqhj.y9vz7wf&x=0&y=o1g2g9
Fri, 09/03/2010 - 01:03
#9
That's an interesting
That's an interesting situation, teaching kids about classic bikes- sounds like God's work.
One issue that comes to mind is the eccentric nature of the pre-1970 BMW motorcycle. Talk about being extremely far from the beaten path in terms engineering, last I have seen no one uses Earl's forks, centrifical oiling systems, plunger style rear suspensions, and magneto based ignition. It's a great lesson in engineering to understand the pre-1970 bikes, but it's a complicated lesson teaching these odd approaches without being able to abstract from more conventional designs. The post 1970 bikes share most of the conventional attributes most modern bikes use and except for shaft drive and a horizontal engine, they are comparable to almost any other bike. May be an easier lesson to teach....
Fri, 09/03/2010 - 08:45
#10
Actually, a lot of these
Actually, a lot of these things were conventional at one time or another. BMW was hardly the only manufacturer to use the Earles design, several of the Italian makes did as well, and MV Agusta held some championships with their Earles forked bikes. EML and Ural both still sell forks with this design because it works so well in a sidecar situation. From the late 30s to the mid-50s nearly every motorcycle that had a rear suspension had a plunger rear suspension (but keep in mind that the "/2" type bikes have a full swingarm and not a plunger set up). The British engines of the era had a "sludge trap" in the crank that was expected to be cleaned out. Magnetos were in use by small two strokes into the 80s, but mounted on the flywheel.
It's my contention that there is not only a leading edge of technology, but a trailing edge as well. If you are at either edge, things are mysterious and unkown. It's not that BMW's designs are strange and unusual, it's that we're looking back a long tme, technologically speaking, and the world has moved on. BMW has always been a conservative company and their designs were not crazy for their times.
Fri, 09/03/2010 - 20:53
#11
Forget about a BMW. If your
Forget about a BMW. If your program has serious money and is considering dabbling in a retro project, I'd go Harley based. Vintage BMW bikes are odd, slow, parts are expensive, and they have always represented conservative machines that don't lend themselves to modification and, let's face it, primarily appeal to rich old old folks who appreciate their odd-ball engineering. Of course, the guys on this site are probably very flattered that you would consider a /2. But unless you have a bunch of silver haired 50+ high schoolers in your class, dive into something a little more hip. If your students are going to put in the time and effort, make sure they are investing in something that really captures THEIR interest. I would think that kids these days relate to the BMW brand due to the expensive and exotic cars they produce; not so with the motorcycles. It's pretty obvious that the best old bikes for kids to fiddle with are within the vast universe of Japanese offerings. Us old farts have to remember that 20 years ago is considered vintage for young folks. There were some pretty sweet performing Japenese bikes from that time period... Good luck with your project!
Doug
Sat, 09/04/2010 - 18:20
#12
Aaaw Come on
Aaaaw come on Doug, thats no way to talk about Darryl and Kurt (silver haired +50 maybe) but old farts, well ok but nice guys nevertheless. Serioulsy I think a challenge would be fitting for these students as challenge is the means to gain knowledge and any old rough nut can spanner a Jap bike, take to it with an angle grinder and come out the other side with something to show. The real art is taking a /2 and doing something thoughtful and unique.
See example of what Ecco BMW have done along with others and there are some amazing modifications.
Keep us posted Richie.
Tue, 09/07/2010 - 18:59
#13
Well thanks for all the
Well thanks for all the insite. I still would love to do a BMW and today was the first day of school so I got togather with my old team and we talked about the next project a bit. first they reminded me that we need to finish the TZ before we get to wraped up in the next project ( you gotta love kids that have more sence than their teacher!) but I did remind them that if and when I sell the R/X project one of the things I had posted was that I was intristed in partial trades so lets see what we get. As of right now we are looking at a fether bed slimline with "Roadhugger"? forks or somthing like that also a Rickman 125 roadracer roller, im not sure what that is but I was told it was between a 58-62? ill let you all know if I get any other odd ball offers, also if anyone has a project or basket case they would part with please let me know, If I have the dough Ill let you know because remember this ALL comes out of MY pocket the school district gives me NOTHING torwards these projects just the room and kids. which I cant thank them enough for!!!!!
Sun, 09/12/2010 - 00:02
#14
Good luck to you. I still
Good luck to you. I still think an old BMW is going to bleed you dry as far as cost. I've been getting rid of a bunch of older Yamaha parts as well as a few BMW items on ebay. The BMW stuff consistently goes quickly and at high prices. The Japanese stuff is pretty much a giveaway. The restoration crowd on this site will tell you that a restored pre 1970 BMW can cost you upwards of $10K to do these days and there are a lot of folks out there that would cringe at the thought of chopping up a /2. You'll be competing against this crew for any decent basket case /2 and they'll run you into the ground bidding up the price of parts on line. Yes, you're better off looking for a post '70 airhead, but the parts are still not cheap. I'f your heart is set on a BMW, teach your students the most important lesson of all; buy the best one you can afford.
Have fun!
Doug
It looks like your class is doing some cool things!
If you hunt around here, you'll see a lot of discussion about working on the BMWs. I'd probably recommend that you look at the post-1969 "Airhead" bikes. They were built for 25 years and not only are lots of parts available in the used market, but BMW continues to provide new ones, too. The general things to keep in mind when choosing a project are the features of each "generation" of the Airheads.
The 1970-1980 bikes, which are the /5, /6 and /7 series, all have aluminum cylinders with cast in iron liners. They all have points ignition. The /5 series (and the low end R60/6) have drum brakes, the rest have disk front and drum rear. They also have a kickstarter as well as electric start. The master cylinder for the front disk on the /6s and /7s is hidden under the tank. The disk brakes are from ATE and are somewhat wooden. The late /7s are the first to come from the factory with cast wheels instead of spokes. All but the low end /5 and /6 bikes, and the special R90S (the top /6 bike), have CV carbs; the rest have slide carbs (the R90S has accelerator pumps in its Italian sourced Dell'Orto carbs).
The 1981-1984 bikes introduce electronic ignition and nikasil plated aluminum cylinders. They are known to have a weak spot in that the stock valve seats don't transfer heat well, and sooner rather than later the valves distort and recede into the heads. New seats (and valves) fix the problem. These bikes have Brembo disks with much better feedback.
The 1985-1996 bikes have the single sided "monolever" rear swingarm. These have a stiffer frame and handle more precisely.
All of the bikes in this era have a 12V alternator on the crankshaft, a rectifier board ("the diode board") above it under the front cover, and a voltage regulator under the tank. You'll hear a lot about how this is a weak point on these bikes, but I think in the context of the era, that's not so. The 240 watts that most of the bikes make were by far the best of any bikes in that time except Honda's Goldwing, which also produced 240 watts. But, over a long lifetime, the two parts that may commonly fail are the diode board and the rotor.
If you're interested in an earlier model, you may find it prohibitive, as the pre-1970 bikes (the so-called /2s) are going up in value. They are much simpler bikes -- 6V generator, magneto ignition, dual leading shoe front brakes, kickstart only -- and somewhat excentric compared to British or Japanese bikes.
I hope that gives you an overview you can use.
VBMWMO Webmaster,--Darryl Richman
Rider #52 in the 2012 Cannonball--follow my blog!
http://darryl.crafty-fox.com