From the Clinic Article...

"Timing Adjustment Screw

This is the "Green" colored screw just above the Blue duration adjustment screw. The" Mucker" said it best,,,,, This upper screw adjusts the "timing" of the squirt. By altering it's setting, you can advance or delay the onset of the fuel squirt. But probably, it won't have to be touched."

The last sentence discounts what I believe to be the most critical aspect of solving the carb cough....the timing of the accelerator pump squirt.

I have found on both of my stock carbs that the timing cam is adjusted from the factory with a small gap between the cam and the pump plunger. As this allows the throttle plate to begin opening before squirting the gas, a sudden lean condition is allowed to develop which is commonly understood to be the primary precuror of the carb cough. The cam-to-plunger gap also seems to facilitate air bubbles in the discharge tube, thus causing a periodic sputtering of gas instead of a solid, perfectly timed stream of gas hitting the t-plate.

Furthermore, turning in the duration screw masks the true problem...timing...by reducing the amount of available fuel to burn/backfire through the intake tract. So, the apparent diminution of the cough by reducing the duration of the stream foments the logical, though mistaken, belief that you are solving the problem.

In short, if you are experiencing carb coughing on an otherwise properly set PMS and jetted bike, I recommend that the order of resolution to the carb cough should be...

1) Advance the accelerator pump tIming.
2) Increase the idle speed if it is below factory setting.
3) Fill with solder and redrill pilot air jet to .020"-.030"

Please reply back with your experience.

--Chris