Some time ago a very embarrassed Airhead owner contacted me about how to ‘fix’ his carburetors. He has Bing CV carbs, and replaced the diaphragms, floats, etc. himself. Frankly, he is a bit ham-fisted. He also hates to ask for advice. He proceeded to nearly destroy his carburetors. The many e-mails with him prompted this article. There is a LOT of information in this article, and lots more on the author’s website. Carburetor work is not very difficult, easy to learn, and once you have worked on your carburetors, perhaps at such at an Airhead TechDay, you will wonder what all the fuss was about and you will find that it is easy the second time, and you might hardly need to refer to this article …or one of my others on carburetors…again.
I have my own ideas about when one should consider working on your Bing CV carburetors (and fuel tank and petcocks!):
YEARLY: depending on mileage and use: clean/dump float bowl contents, check corner bowl jet to be sure it is clear/open, possibly replace float bowl gasket if poor; empty gas tank, remove petcock(s), clean tank, dry it, clean petcock screen(s), possibly service petcocks internally if they are getting quite stiff to turn; or, if leaking. Inspect fuel hoses. I consider these things part of carburetor servicing. Failure to service the fuel tank will eventually be costly.
5,000 mile intervals: synchronize the carburetors, but ONLY AFTER the valve adjustment and ignition timing adjustments are checked FIRST.
30,000 mile intervals: replace float assembly (if original one piece assembly). Always also replace the float needle and clean out the central jet assembly. Replacing the float assembly is UNlikely if you have the alcohol-proof separate floats that Bing now offers. However, if you have those, be sure to replace the float needle and
{mprestriction ids=”4,5,6,8,9,10,11,12″} check the adjustment of the flimsy brass floats bridge, info on the Snowbum website in its own article on these independent float kits:
http://bmwmotorcycletech.info/bingindependent.htm
