Hi,
I finally changed out the Fatboy bars on my 05, put on Heritage bars which are great. Problem, I used stock grips for now, and throttle side I just loosened and slide off, and slide on new bars. Now the throttle does not snap back. I have tried loosing the cable adjuster, still does not snap back. Also have the throttle tension nut loose. Could something have shifted internal, even though I just loosened the grip, I can not figure it out. Help.......

 

On the end of the thumbscrew,inside the housing there's a little wedge shaped piece.It probably fell off and is wedging itself against something.I'd check that first

 

You may have the grip pushed too far up and the end of the grip is rubbing on the end of the handlebar. Should have about 1/32 clearance back there.
Ron

 

Dr G...that makes a lot of sense, will check to see if that is it...thanks