Last week I had a thread going about the harshness of my throttle response when transitioning from full off to on, causing the bike to lunge, as well as the occasional cough out the carb
, and even stalling at low speeds or standing starts. This was especially annoying when trying to modulate the throttle through turns or simply maintaining cruising speeds.
It was suggested I adjust the accelerator pump, so I did. (See Tech Article for details)
At the stock setting, the "Accelerator Duration Adjustment Screw" wasn't even touching the accel pump cam, which controls the amount of extra fuel squirted into the throat of the carb, every time you twist the throttle from off to on.
I could see, as I twisted the throttle, how the significant amount of fuel being squirted into the carb could result in a temporary rich mixture, which would explain the rough transition and carb cough.
So per the tech article, I loosened the lock nut on the adjustment screw and dialed it in as far as it would go, but even at that, it only *barely* touched the cam and had little effect. Then I removed the lock nut altogether, allowing for an additional 2 mm
more adjustment, which was enough to make a difference. Now the accelerator pump squirts about 1/3 to 1/4 the amount it was before.
The results were good. The throttle response is much smoother and after a 250 mile ride, the carb only coughed once. Also, as some mentioned, I can see where this would improve gas mileage too, considering how much fuel was previously being squirted each time the throttle was barely tapped.
It would also seem that this could help if you're having trouble dialing in your PMS
, by eliminating erratic lean/rich conditions? [Maybe the experts can comment on that]
So, if you're experiencing rough throttle transitions, or carb coughing, you may want to give it a try.
...On a side note... Question for the carb experts: Considering it's now so far from the stock setting, are there any downsides to setting it up as described above?