I have a 2000 Heritage classic and it has a carburator. I added a big sucker. My engine has started to stall at stop lights. It will idle fine but when the light changes and you accelerate it stalls. I try to restart it and it turns over but no start. I shut it off and turn it back on and it will start. Once you get it moving it runs fine. However at the next light it will stall again when you try to accelerate. This seems to happen the longer you sit at idle at the light.

 

Try adjusting the low speed jet and double check the cable adjustments,,,,,

 

Check your accelarator pump.