I have been looking for some info on CV mods. I have a 93 FLHS that I did a rering w/SE heads and Andrews EV59 cam, S&S lifters, Spyke Stampede ignition, HyperCharger and V&H Longshots. By much research and wrenching I drilled a 3/32" hole in the butterfly to get it to idle and have an idle mixture and use a Sporty needle w/.025" shim, a 50 pilot and 205 main. I also drilled and radiused the slide. The bike ran lean at steady speeds which improved by clipping 2 coils off the spring. The bike smooths out and runs great at 4k rpm on up but thats 90mph+ ! I would like to know the purpose of the lighter SE spring and how to balance the spring pressure to my setup. The bike is a blast to ride and gets 38 mpg.