I'm going to hazzard a guess here, if the cables in the bracket don't stick, but putting the anchors in the cam and it sticks, AND the cam rotates freely feeling only the return spring and no jamming/gummy/bind/etc....I'd wager my lunch money they are too tight.
Do you have to fight to get the sleeve ends in the bracket after putting the anchor ends in the cam, even with the adjusters backed off to as much slack as possible? I'm thinking you don't have enough free cable extending past the sleeve to have the appropriate slack. There should be something like 1/16-1/8 in of wiggle in the throttle grip where you see the cables flex a hint on the cam before they start to turn the cam & throttle plate.
it is rather difficult to put the second cable into the bracket, and if i had one of them tensioned it would be almost impossible (putting a flatblade under the locknut and forcing it up with all my strength). theres two nuts on the pull cable housing... should they both be on the top or one on the top one on the bottom locking the cable into the bracket... my dad was wondering that.
2001 Honda Rebel 250
1981 Kawasaki KM100
1987 Honda Rebel 450