The bing type T116 carburetor is arguably one of the simplest carburetor designs there is. Even so is does it’s job. There isn’t a lot that can go wrong with this carburetor, and once set shouldn’t need any adjustment for a long time. However, after many years of service, like all mechanical parts they can wear, leading to most people including myself tending to endlessly fiddle with the adjustments in order to find the correct balance between idle and running. We are trying to compensate for a worn carburator that is now not within it’s specification.

If worn, changing the jets, needles, float, springs and washer is an easy task, which involves a simple swap, and hopefully it has cured your carby problem. However, more than likely it has not, since the culprit to our poor performance is the only moving part in the carburetor, the slide.

At the point of idle our carburetor essentially relies on one very small orifice to deliver the correct amount of fuel into the engines combustion chamber. The amount of fuel is determined by our idle adjustment screw but this relies on the air that is drawn in over the idle hole to be precisely controlled. The carburetor slide controls that by being raised and lowered when throttling up and down.

At idle the air must flow exactly over the idle jet hole in order to draw an exact predetermined amount of fuel for smooth idling.

If the slide is worn in relation to the body our air delivery system is uncontrolled especially at the point of idle where we need it to be concentrated and funelled over a small area. The air is now not only passing under the slide it is now passing around the sides of the slide between itself and the worn body. We are getting erratic air delivery which leads to a poor idle and the tell tale sound of a worn carby that click, click ,click as the engine takes it’s next breath and the slide flops back and forth in the carby body.

As mentioned above the swapping out of needle and jets is an easy task however what can be done with a worn slide and carb body to bring it back to good service.

Bruce Chessell of www.tritonmachining.com in Ontario Canada has the answer to that problem. He expertly re-bores and hones the carburetor body to bring it back to exactly round and perfectly smooth. He then takes your old slide turns it down and re-sleeves it with a brass sleeve. The sleeve is then machined to the exact size and tolerance for a perfect fit in the carb body. The slide profile is then milled back in.

If as in my case the slide-locating tab is very worn the old tab is ground off and a set screw fitted for central location.

We now have a carby that is as good as new and some would argue better than new since the wear characteristics of brass on masak are said to be better than the same material on itself.

This is the slide, one can see the very worn central locateing tab.

The carb body and slide prior to machining.

The reconditioned body, one can see the small idle jet hole.