R11 brake plate breaking

[Darryl.Richman]

darryl-

you asked "...And how do you find out what is "correct" in each of the 5 series? Seems like BMW made a bunch of running changes."

just read off the part numbers stamped on any given part-then look at a catalogue picture.
if you look at a copy of the original parts books-available in reproduction-you can see that unlike the later parts books, it's set up by this clever but needed illustrated chart by part; you just look for the picture-all the various years stock numbers are there-then you can find your existing part number with a check in the accompaning graph that tells you which year it was used in-or with reverse engineering, you can see which versions of each part you need by year, all listed by bmw internally stamped numbers.

for extra fun, you can also use it to find service and replacement parts on your bike done way back then- hey, wait a minute! this part number corrosponds to a year and a half later than my bike! i guess the original owner layed it down so the dealer used the newer stuff...
even some of the nuts and bolts changed numbers and thread counts...!As I've got you guys surrounded, with my R52 and R12 projects, I may have to get an R11 parts book. BMW is notorious for making running changes as they went, and I bet looking through an R11 manual will explain things to me about my R12, and maybe even my R52...

[Barry Robin]

As I've got you guys surrounded, with my R52 and R12 projects, I may have to get an R11 parts book. BMW is notorious for making running changes as they went, and I bet looking through an R11 manual will explain things to me about my R12, and maybe even my R52...

i feel like we're in the wagon train circle and you're the apaches...!

sounds like it's a good idea of yours, to get the R11 parts book-if nothing else for the learning curve. try to get the later version of it from the series 4 or 5: it contains all the compiled running changes by series. you can easily see that the series 1 parts are left over R52 (remember, the R11/16 was originally simply an R52 (R62?)dumped in a star frame; the last changes show the bike as an almost complete R12 minus the plunger forks...)

and you wrote: " ...they made 8300 of them. That's double what they made of the R52..."
-ah, but they produced those 8300 over a five year span-and the biggest production year was in 1930 (the smallest was 1931, as the depresion hit germany), while they were still using up existing parts, so all they really had to do was pop out the frames.... how long did they make the R52? '26 to '28?


here's a sidebar: the only reason my bike survived intact is because it had been in a front end collision in about 1933 (based on the replacement parts and some poor welding up of the steering neck); it was dumped in a garage in east berlin and stayed there untill it was unearthed in the seventies. if it were running during the war it would most probably have been melted down along with the rest of those crappy older models that no one wanted...

and yes, the carb is the same as on your R52. they used it untill they switched over to the sum.
i've got to ask: doesn't that constant fiddling with the mixture lever drive you crazy? it did me, so i mounted a sum carb instead (with actual real jets!) and it does indeed perform much better, thank you. i've got enough to pay attention to driving around in city traffic without trying to find my third hand...!

[Darryl.Richman]

i feel like we're in the wagon train circle and you're the apaches...!Sorry, no Indians in my garage.

sounds like it's a good idea of yours, to get the R11 parts book-if nothing else for the learning curve. try to get the later version of it from the series 4 or 5: it contains all the compiled running changes by series. you can easily see that the series 1 parts are left over R52 (remember, the R11/16 was originally simply an R52 (R62?)dumped in a star frame; the last changes show the bike as an almost complete R12 minus the plunger forks...)

Are you aware that the R11 doesn't have a "star" frame? I believe that misnomer goes back to LJK Setright's Bahnstormer. Instead, it's a starr rahmen which is just good German for rigid frame. (I always wondered what it might be about a pressed steel frame that made it look like a star...)

and you wrote: " ...they made 8300 of them. That's double what they made of the R52..."
-ah, but they produced those 8300 over a five year span-and the biggest production year was in 1930 (the smallest was 1931, as the depresion hit germany), while they were still using up existing parts, so all they really had to do was pop out the frames.... how long did they make the R52? '26 to '28?

So, on average, they produced the same number as R52s per year. Anyway, it seems like there should be a lot of R11s still around.

here's a sidebar: the only reason my bike survived intact is because it had been in a front end collision in about 1933 (based on the replacement parts and some poor welding up of the steering neck); it was dumped in a garage in east berlin and stayed there untill it was unearthed in the seventies. if it were running during the war it would most probably have been melted down along with the rest of those crappy older models that no one wanted...

A friend just acquired an R62 motor, trans, driveshaft and gas tank from an estate sale. The dearly departed had bought the R62 in the mid 50s to use to power a boat project. Threw away the frame and other bits he didn't need. I was a bit flabbergasted at the idea of that last part, but my friend pointed out that it was just a 25 year old bike at the time that nobody wanted.

and yes, the carb is the same as on your R52. they used it untill they switched over to the sum.
i've got to ask: doesn't that constant fiddling with the mixture lever drive you crazy? it did me, so i mounted a sum carb instead (with actual real jets!) and it does indeed perform much better, thank you. i've got enough to pay attention to driving around in city traffic without trying to find my third hand...!

So far, I have about 30 miles of driving the R52. Right now it's still an adventure, and I love messing with it. It's so... weird, and different, and - yes - fussy. It's bound to get old eventually, I suppose. Ask me when I have a couple thousand miles on it!

[Barry Robin]

i had to smile about your notation about the correct translation of the so called starr frame-wondering if you're tired of having to correct people too?; yes, i've always been aware that it's really german for rigid and not something with five points, but over the years i've gotten tired of informing people that Mr. Setright can't seem to translate german!
com'on now: how many times have you had to tell people? lots, i bet...sometimes i just think that it's easier to think: hey, this conversation's in english with a bunch of english speakers-and though the word's wrong, everyone still uses it, so what the hell...


you wrote:"...So far, I have about 30 miles of driving the R52. Right now it's still an adventure, and I love messing with it. It's so... weird, and different, and - yes - fussy. It's bound to get old eventually, I suppose. Ask me when I have a couple thousand miles on it!"

weird and fussy is a good way to describe it. once you get used to it, it's really just fine-though it's still fussy!

i really shouldn't be too snitty about the mixture lever; i only changed it over because, in the long run, it was too much to want to deal with in san francisco traffic (and now in dublin traffic!)
if you end up mostly taking it out on sunday drives up over highway 17, i wouldn't think there'd be a reason to fiddle with it at all.

i've sent you over a picture of my bike (via your website email). you can plainly see that i've cheated with a few modernizations like blinkers and rear view mirrors. i know it's wrong, but i considered them as safety measures.
is there any way you can post it here for me so dan can get a closer look?

thanks,
-barry

[Darryl.Richman]

I'm afraid I haven't seen your email. You can send it to me directly by clicking on the little email button at the bottom of this post. My website address gets so much spam, I have a very strong filter on it. You have to leave the [cfweb] prefix on the subject line or it automatically goes in the trash. I can put your photo up on my server, and then I can post a link to it here. I'd love to see it!

I'm having a tech day here at my house in 2 weeks (4/15), and there's vintage picnic on June 11 at Vasona County Park in Los Gatos. Any chance you might come to either one?

I don't consider mirrors or lighting upgrades cheating. I've added a brake light (dual filament bulb, too) to my R12, and will probably do the same for the R52 when I get it over here. I will probably also set up some bright LEDs for tail and brake light functions, around the license plate. These things can be wired in so they are easily removed if one wants to show a bike.

The Kradrider list folks (http://uk.groups.yahoo.com/group/kradrider/) know that it's a starr rahmen. I'm kind of surprised at how much reach Bahnstormer seems to have had; I think it was already out of print when I bought my copy in the mid 80s.

Does your bike also have a twist grip for the timing? That seems weird to me!

[Barry Robin]

i'll try reposting my letter to the PM here, thanks.

i'm afraid i'll have to beg off on showing up at the tech day this year; remember that my bike and i are now about 8,000 miles east of your house. hmmm... maybe if i catch the ferry out of dun laoghire i can get the ferry captin to take a detour!

i've done the brake light refit too (listening here, dan?)-it's a must for driving on the street! without it, one feels like it's only a matter of time before someone decides to notice you've got a sign on your bike that says "kick me". (have you noticed that hardly anyone remembers that holding your left arm downwards means "stopping"?)

on the twist grip timing: i have no twist grips at all-just the same lever sets as your R52. the only difference from stock is that my mixture lever is now just a dummy since switching over to the sum carb.

on a side note: any idea what ever happened to darwin motors, up in the city? it-and he-seems to have dropped off the face of the earth.

[Barry Robin]

darryl, it looks like it's no-go on posting to you...your direct email link isn't listed (just the web site), and the PM won't let me drop and paste a picture...

o.k., you can stop laughing right now, mister.

[Darryl.Richman]

on a side note: any idea what ever happened to darwin motors, up in the city? it-and he-seems to have dropped off the face of the earth.They went out of business a year or two ago. A guy I know bought their inventory, and in turn sold off everything newer than 1969. I helped him move some of it, the place was a mess. Even some customers' bikes were still there.

The story I heard was that the owner had grown bored with the shop, and moved to Hawaii where he had bigger fish to fry, so he left the manager to run things, which wasn't a recipe for success. So he closed it. I used to see their ads, but was never in the shop when it was open.

[olebmw]

I guess if I put the correct twin slide carburetor on my R11 I will have to change from the twist grips and use the two lever set up,Is that correct? How do you use the levers? Do you open both slides the same amount ? What year was the single slide Sum first used?

[Barry Robin]

sorry dan, if i made the carb question sound more complicated than it is.

first off, if you've got the correct 1930 bmw carb on it now-and it works- there's no real reason to swap it out to the twins, unless you are looking for the ease of operation-and more horsepower. but if you do decide to fiddle-and you know i have no problem with this-make sure you do it for the right reasons...like you want to! ("so it's not perfectly original for the YOM...big deal!")

first off, there's a detail problem involved: if you want to keep it %100 correct, you should know that the twin carb amal-fischer set-up was only available on R16's; the twin carbs only became stock on the R11's in the series 4 (1934).

the first year that bmw offered the side-slide sum-as a option-was 1930, but the first year that it came standard was 1931. honestly, if you're going to change things, i'd suggest the sum over the dual set-up: it's correct for the year and you can utilise the existing set-up with less fiddling with everything else.

if you do update the carbs to twins, be aware that this also involves losing the manifold and plugging the air intake from the rear of the tranny. no big deal there.

now on to the levers...:

no, you don't have to use the levers at all if you don't want to (but they are neat looking); you can use the use one of the three twist grips offered. i wouldn't worry too much about accidentally using the wrong set, as they look very similar to the average enthusiast-and most judges-but as the R16 sport version is rarer than hen's teeth, i doubt that you'll ever find one for sale-ever.

the early twist grips are for one cable only and come with a mixture lever on the top, the later ones don't. if you have one with the lever, just make up a dummy cable to look correct.

to hook up both carbs to the single cable, bmw offered a 1 into 2 splitter, but i've never seen one for sale. the closest alternative is to use their /5 version..it looks almost identical.

hope this helps...