If you want to improve the throttle response from your OEM CV carburetor for about $3.00, replace the vacuum piston spring with the spring from the Screamin Eagle 44mm CV (part number 27728-99). Stock spring tension is 200/290 grams versus 130/210 for the new spring.
I copiedthe abovefrom nightrider.com. Can anyone accredit any validity to the above statement

If you got it from KnightRider it's got to be correct. These guy's know their sh!t. Hell for three bucks and a 1/2 hour what do you have to loose. In Texas that's
1/2 a beer job. Oh I'm in Cali. so would that be 1/2 a glass of whine.:D:D:D Steve

On my 2001 FLHT,from the factory the cv carb was like a piece of trash.The dealership instlled a Dynojet kit,along with a K+N filter.What I was unaware of when the wrench hand installed the kit he overtightened the emulsion tube,splitting it up the side.I onlt found out about it when it was ran on the dyno.I got a rebuild kit from www.Harleyperfomance.com (http://www.Harleyperfomance.com)
It too has a lighter spring,along with that plus some tricks I have learned in the past,the throdlle is lighter in your grip,and it's really fast to come up get's rpm build fast,yes it's a much better carb with this spring setup.I don't know if it's lighter,or heavier then your spring,but i can tell you it works great:)