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Bing carb issue
Bing carb issue
Re: Bing carb issue
Dave
- Flx48
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Re: Bing carb issue
Best-
George
Re: Bing carb issue
Re: Bing carb issue
Dave
- schrader7032
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Re: Bing carb issue
'78 R100/7 '69 R69S '52 R25/2
Fast. Neat. Average. Friendly. Good. Good.
- Flx48
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Re: Bing carb issue
And the idle circuit is like a smaller, even simpler, miniature one speed carb.
Gasoline is introduced from the float bowl, passing under the main jet, and then up through the idle jet at a constant rate.
Meanwhile, air is introduced to the idle jet via the smaller of the two bores seen below the carb's main air intake bore. (the small bore closest to the float bowl)
The idle air adjustment screw enters this air passage near the idle jet end of the passage.
The idle air adjustment screw has, as its primary function, the job of controlling the idle mixture.
It is screwed in to richen the mixture, (by blocking off air) or screwed out to lean the mixture. (by allowing more air to pass)
The idle air adjustment screw also has a secondary function.
The screw has a very small bore through its cross-section down near its pencil point end, and another midway along its threaded portion, and those two holes are connected by a line bore lengthwise down the center of the screw.
This creates a passage, a vent, from inside the carb to the outside of the carb.
A minimal amount of air enters through this vent, but this vent could be totally blocked, (many are...) and the idle screw would still balance the gas/air mixture perfectly well, as the vast majority of air enters through that passage below the main air intake.
The reason for the vent passage in the idle adjustment screw is to drain any excess gasoline that may leak into the float chamber, before it can pass through the carb, into the head, and end up washing the cylinder walls and contaminating the oil in the sump.
This vent works simply because the idle air adjustment screw is located lower than the main intake to the head.
The reason for this vent is to protect the engine from excessive flooding.
Viewed from present day engine design the Bing is crude; but when viewed from the days when it was current, the design was simple, practical, and effective; and another part of what made the bike's reputation as long lasting and low maintenance.
Best-
George
- wa1nca
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Re: Bing carb issue
Tnx George
Ps:
Saw your side car rig at a Nova rally about 4 years ago
Tried to catch you but lost site on the small roads !!
54 R51/3, 55 R50/Velorex 560 sidecar, 64 R27, 68 R69US, 75 R75/6
Ashfield, Ma
USA
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Re: Bing carb issue
R69S - R60/2 - R67/2 - R51/3 - R69