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Need help with a 1958 R26!

Hey everyone,
Writing here because I bought an Dove white R26 last summer and was starting to work on it. While the bike runs, I immediately ran into some issues. When looking at the carburetor I saw the previous owner had slapped a Mikuni carburetor on, which the flange was hammered on just to get it to fit. So I went forward and purchased a rebuilt Bing 1/26/46 carburetor from Germany. However once I mounted that it started leaking fuel everywhere so I have to tinker with it. So I have questions for the forum....
-Does anyone know what model number Mikuni fits these model BMWs because Id like to try fitting it. I find that many of the models do not have the right size to fit as an exact replacement to OEM carbs.

P.S. I am not a professional mechanic, Im just an average joe with interest in these beautiful vintage BMW bikes.


Heres a pic of the beauty:
IMG_8275.JPG
 
Welcome to the forum! I can appreciate the singles...that's a nice Dover White version. I would think that the Bing can work just fine but there could be issues with the replacement Bing. Might be that the float doesn't work right? Is it brass? Brass will stress-crack for no reason at all...when it does it fills with gas and sinks. Is it possible for you to take pictures of the current Mikuni setup installed as well as a picture of the flange on the head? The BMW head on the singles, as least on my R25/2, have two bolts horizontally which mate with the flange on the carb side. What is your setup? I thought that the flange on the Mikunis had holes top and bottom. One needs an adapter in that case.

There have been some discussions in the past about Mikunis but generally for the twins however some for the singles. Here are those threads.

https://forums.bmwmoa.org/showthread.php?95177-Mikuni-Carburetors
https://forums.bmwmoa.org/showthread.php?98579-Source-for-R27-Carburetor-(1964)

I'd dig deeper into the issue with the Bing before jumping in the Mikuni world. The 1/26/46 carb number indicates that the carb opening to the head is 26mm, so you would need a Mikuni to work with that. Rocky Point Cycle is someplace that does support Mikuni carbs...maybe they can help.

https://www.rockypointcycle.com/c-bmw.html

In a little bit of time, we're going to have to change your forum username once you get this bike figured out! :wave
 
Hey,
So I do not have pictures if the Mikuni mounted because I currently have the carb dismounted off the bike and its cold in Jersey so everything is put away. Here are pictures of the mikuni so you can see the flange and how it was hammered to shorten it to fit the space. I would really like to know what model number this carb is but there is no indication on it. Also the bing is brass so Im sure its a float issue but I would rather have someone who knows more about it look at it.IMG_5367.jpgIMG_5366.jpgIMG_5364.jpg
 
I have little to no experience with Mikunis...I don't understand why the mangled end, which I assume was supposed to be connected to the head intake port. I'd be interested in seeing what the aft side of the intake of the head looks like. Hopefully no damage was done to that.

Maybe other's with good eyes can identify the type of carb. I would also check with Rocky Point...maybe they could look at a picture that you send them to get a better sense of what model the Mikuni is...or recommend one that might work in your situation.
 
Back with answers. Also back with questions

Checking back in I know it’s been a while! I apologize but being a nurse during the pandemic has not been very rewarding in terms of time off and away from work. To start, Rockypointcycle was very helpful with a replacement with the mikuni issue I was having, however I opted for an OEM version I found online fully rebuilt. So currently I have the OEM bing in my possession. Anyways, I wanted to ask if anyone local to NJ can rebuild/ fully service this 1958 motor? I’ve taken it to max bmw who quoted me roughly 10k for full workup including a slinger service. They would take of the top head and service it top to bottom. I wonder if anyone else could do it for under 5k? Im willing to drive as far as Connecticut to get it serviced. I’ve called local shops here in Jersey without much luck. The bike runs but I can tell it needs to be looked at. Hoping to hear from you all!
 
engine work

You might want to look into Bench Mark Works in Mississippi or Boxerworks in GA just to at least compare prices. Either way, you'll be dealing with people who know what they're doing with an R26.
 
Hey all checking back in!

So I decided to rebuild the entire motorcycle myself. While I was a bit clueless about where to start, Ive made some good progress and will post here the final photos once its done. The reason I am checking in is because Ive run into another issue! (Guess i'm still clueless!) I took some parts to get chromed and one of the parts was the rear wheel axle which isnt all the same size however I only discovered that when I realized the gentleman who chromed the part for me sanded all to the same size. Ive drawn out a diagram of the rear wheel axle and wanted to know if anyone knows the dimensions of the axle in terms of A,B, and C on my diagram. Im going to get this part custom made to fit. Hope to hear from you guys!IMG_9617.jpg
 
Bummer. Seems like a bit out there to sand it all to one diameter!! :dunno I don't have that animal around. While you wait for someone with an R26 to get back to us, maybe give Vech a call at Bench Mark Works. Certainly they would be able to find that info...I looked on their website and didn't see a rear axle offered, but I'm sure they can help out.
 
I second engaging Vech or Richard at Bench Mark Works, they are an excellent asset for Vintage bikes. Are you familiar with Salis out of the Netherlands yet? They have fantastic exploded views, decent prices and just a few items can make shipping worthwhile also. Those two shops were invaluable to me when restoring my '55 R50. Bench Mark Works gets the nod as the go-to shop though due to the unselfish help and advice they provided me numerous times.

Here is your rear axle at Salis, Bench Mark lists it also. I would often use the exploded views on Salis' page to find the part number, then look it up on Bench Marks page since their page is not nearly as user friendly for finding items like this. https://bmwclassicmotorcycles.com/index.php/catalogsearch/result/?q=36313004158
 
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