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Bing CV Carburetors, Part 1 of 2 parts.
Bing CV carburetors are used on most BMW Airhead motorcycles
© Copyright, 2014, R. Fleischer
For a well-done overhaul article...step by step...with 44 pictures....see BMWMOA magazine, BMW-ON (BMW Owners News), March 2003, for an article in great depth by Gary L. Smith. You can probably get that back issue at http://www.bmwmoa.org. From that main page, click on left side for Country Store, and then on the Country Store page, go to Back Issues.
I have SOME nitpicking on that article:
1. See my notes in the article you are reading.
2. Use faint amount of silicone grease on all O-rings & on enrichener parts (do NOT overdo this, you do NOT want to plug jet holes).
3. If doing a complete overhaul, which involves removing the butterfly to replace the throttle shaft O-ring (be sure to silicone grease that one & be SURE to MARK the butterfly for correct refitting: something like TOP, OUTER; or TOP, facing REAR...or something of that sort....BEFORE you remove the old one. HOPE that the previous workman did not install yours backwards, because it can be fun to figure out unless you know what it is supposed to look like. In the article you are now reading I have photos of what it IS supposed to look like..... & NOT look like.
4. The article you are reading, below, has considerably more complete information about orienting the enrichener parts.
A basic MINI-overhaul can be done with the carburetors in place on the engine. This is often quite enough. Two articles, the one you are reading....and http://bmwmotorcycletech.info/bingcv-2.htm (which is article 3B) are not just about how to overhaul a Bing CV carburetor. These two articles are specifically designed to fully inform you what you need to know, as an Airhead owner/rider, about these carburetors. The one exception is if you have an R75/5, which, if stock, has a particularly troublesome version of the Bing CV carburetor, as it was the first generation of these carburetors. For these carburetors, you should review both of these above two linked articles AND, in particular, review myarticle #6: http://bmwmotorcycletech.info/earlybingR75CV.htm
What follows is NOT a step-by-step how-to article. This article DOES cover every important thing you really need to know about working on Bing CV Carburetors....and, used together with the above linked articles, you will be well-informed.
NOTE!....there is no overhaul nor adjustments article on this website for the Bing model 53 'slide' carburetors, as used on the R50/5, R60/5, R60/6, and R60/7. They are straightforward. They use the SAME floats as the CV carburetors. For acceleration pump parts check with both BMW & with Bing Agency. Some Bing carburetors, such as the R60/6 and R60/7, use an acceleration jet assembly in the central assembly, these parts all come out mostly at one time, same as those carburetors without. One of the Airlist Members made some 'washers' that fit the acceleration pump, making them of nylon material. 3.556 mm x 0.33 mm. I have not confirmed this works/fits.
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