Welcome to the site !!
What it sounds like is the throttle cables are mis-adjusted .... at the Throttle Body , (remove the tank) you will see a adjuster nut on each cable , one for the push cable and one for the pull cable , turn your bars all the way left and then right , twisting the throttle at each end , if it sticks or returns slowly then check for the cable binding , then loosen the 2 cables at the adjusters and repeat , if the throttle snaps back , that is the issue , , then you will just have to adjust the cables so there is slack at the throttle tube when at full lock each direction , then tighten the locknut down and you should be good ..... any fine tuning of the cable can be done at the throttle housing after that , but the main setting needs to be at the throttle body first ........
Hopefully that fixes your issue ...