When adjusting the throttle cables on non cruise bikes , the slack is all taken care of with the 2 adjusters on the cable under the bars. The important thing to realize is that on full throttle you want just enough slack in the pull cable so that the hand grip hits the stop and NOT the carb/throttlebody or you will break cables like no tomorrow. If you open the throttle grip fully and slack off on the pull cable just enough so that your linkage down below just misses the stop by a hair, you'll be in good shape and will not break cables. This way does not stretch your cable when ever you twist the grip to full travel.
Also try the forks full left and right with the motor running to make sure they are not too tight and opening the throttle on full rotational of the forks.
Also on cruise control models...
1. With handlebar straight ahead, idle cable adjusted to full slack and throttle control grip turned to wide open throttle, adjust pull open cable to obtain full throttle opening at the carb/induction module
2. twist throttle grip to full closed position. Check that idle stop screw is touching idle stop with handlebar in straight ahead position, and while turning handlebar from lock to lock if idle screw is not touching, loosen pull open cable just enough so that contact is made through full lock to lock handlebar movement. Also check that cruise cable has slack and is not opening throttle.
3. Rotate throttle grip to WOT and release. Throttle must return to idle position freely. If not check for damaged cables, misrouted cables or binding in the grip
Also see this post too...
Throttle Cable Adjustment Video - Harley Davidson Community
Also try the forks full left and right with the motor running to make sure they are not too tight and opening the throttle on full rotational of the forks.
Also on cruise control models...
1. With handlebar straight ahead, idle cable adjusted to full slack and throttle control grip turned to wide open throttle, adjust pull open cable to obtain full throttle opening at the carb/induction module
2. twist throttle grip to full closed position. Check that idle stop screw is touching idle stop with handlebar in straight ahead position, and while turning handlebar from lock to lock if idle screw is not touching, loosen pull open cable just enough so that contact is made through full lock to lock handlebar movement. Also check that cruise cable has slack and is not opening throttle.
3. Rotate throttle grip to WOT and release. Throttle must return to idle position freely. If not check for damaged cables, misrouted cables or binding in the grip
Also see this post too...
Throttle Cable Adjustment Video - Harley Davidson Community