Boxerworks.com

Could someone explain how this thing works. Have been unable to find either a good diagram or explanation.
I don't have a bike with this type of carburettor, waiting for a suitable R60/6 to appear on Ebay, but like to understand the inner workings.

There's not much information around on the Bing type 53's.

I have no hands on experience of this carb so to learn how it works I would just take it apart and look.

From what I can gather the accelerator pump is in the main jet/mixing tube assembly where there is a small reservoir of fuel which fills when the needle is dropped and is released when the needle lifts. There is some sort of check valve which must be in good condition to prevent the reservoir of fuel draining back down.

https://www.bingcarburetor.com/type53.html#/

Thanks for reply's. As you say a crude none return valve. An extra squirt of fuel just off idle as if the carburettor has an inherent flat/weak spot.

It's in the nature of slide carbs that they have an inherent flat stop when the throttle is opened. The accelerator pump seems a neat enough solution if it works well.

My understanding from memory is that there is a spring loaded element... can't remember off hand if it's a ball bearing or a slug of some other description... contained inside the main jet holder (accelerator pump or fuel pump in BMW speak).

It is below the level of fuel in the float bowl and is full of fuel.

The pump element is pushed down against the spring by the end of the slide needle when the throttle is closed.

As the slide rises, it is pushed up by the spring causing extra fuel to be pushed through the needle jet and into the venturi.

The result is that there is a brief enrichment of the mixture when the slide starts to rise giving a richer mixture off the idle and when the throttle is taken off the overun.

Crude but effective in overcoming the flat spot off idle and initial lean mixture when the throttle is opened.

Rob