Check if you might have installed the enrichener parts backwards, or mixed left and right parts. Check that the gasket at the enrichener assembly is OK, not sucked inwards or pushed outwards. Check float bowl gasket, it MUST be in good condition surrounding the enrichener well area, for complex reasons, explained in simple form here, The enrichener jet in the float bowl MUST BE CLEAR, NOT CLOGGED!Ĭheck the above. Very early Bing CV carburetors have pressed-in float bowl enrichener jets, not screwed-in. Check the tube leading into the well for cracks. Both situations are often much worse on cold days. If one or both bowl corner jets is clogged badly enough, bike might not start at all. bowl gasket or enrichener gasket/screws problem Partially clogged jet at the bottom of the bowl well OR. Starts OK, enrichener (choke) in use, then seems to run out of fuel, after perhaps 15-30 seconds: That is still true for later models, but BMW dropped the recommendation of opening the throttle. That can be a necessity depending on the bike, temperature (does not have to be very cold), & how the carburetors are adjusted. It was in November of 1971 that BMW first, and almost lastly, recommended opening the throttle during cold starts. For those carburetors, you should review the above linked article and the one you are presently reading AND, in particular, THEN review the following one, which is article #6: The one exception is if you have an R75/5, which has a particular, and troublesome version of the 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. Two articles, the one you are reading, and are not just about how to overhaul a Bing CV carburetor. See the fuel section of the Technical Articles List.Ī basic mini-overhaul can be done with the carburetors in place on the engine. There are more than just 2 BING CV carburetor articles on this website.

including details about the plastic tubes, O-rings, clam-shell versus Notes tuning overhaul, needle seats, starting problems plus lots of hints. Thanks for remembering! Thanks, too, for the occasional donation! Snowbum's BMW Motorcycle Repair & Information WebsiteĬlicking on them at every visit helps support this website!Ĭlicking on something inside an advertisement helps even more!

Bing carb manual 33 12 152