need help with carb mod

[DISHO1]

curtis sparks does a carb mod to the 400ex carb. i asked them what they did to the carb and they said the throttle butterfly valve is removed , but i removed the valve on mine and it idle way too fast. the idle adjustment did not do anything to slow it.

on a cv carb the throttle cable moves the throttle butterfly valve and air pressure moves the slide up or down

on a " flat slide" carb the throttle cable moves the slide and there is no butterfly valve

the valve is the restriction on a cv and the slide is the restriction on a "flat slide". that restricts how much air gets by on both carbs and controls idle somewhat.

on the 400ex carb the throttle cable moves both the valve and slide together.

the question is what does sparks do to the carb to get the idle back to where is should be if they remove the throttle butterfly valve?

or do they even remove the throttle butterfly valve?

[nakomis0]

The only thing I can possible think of is when you removed the choke plate and shaft, the increased airflow made it run leaner and a leaner running bike will idle faster. (check the plug or change a pilot jet maybe? beats me)

When I did the stock carb mod I had just the opposite, I could't turn the idle up enough, it would barely idle, and there was no way for me fix it. .... good luck

[DISHO1]

i was talking about the other butterfly valve not the choke plate & shaft.

the throttle butterfly valve is the one at the front of the carb .