After you check the items mentioned by Al, you could check in the engine compartment the cable/throttle tube/linkage return springs.
if the stock throttle tube is worn, the braided cable will catch on the sharp edge, eventually snapping.
I replaced the stoc tube with the attached, and it made a difference...
Also something worth checking is the tension on the return springs on your linkage/carbs assembly.
When I got my VS back in 2013, the springs were much stronger than needed. They applied to much tension on the cable, and the pedal was sticky/ it bound at times ( as it caught on the throttle tube). I replaced with softer springs, and it made a world of difference... unfortunately by the time I did, I had already worn the edge of my throttle cable tube... so I replaced with the above roller throttle tube. All works great now.
I ran a simple test back then by using a wire, & reducing tension from the return springs on the linkage assembly . See attached photo. The change in pedal resistance/consistency was immediate. Pedal no longer stuck. May be worth testing...
Hope this helps!