I have had that same issue.The cable adjustment is very sensitive,they cant be too loose or it will pop off,and cant be too tight or throttle will stick.When you adjust these make sure the handle bars are straight and not to the right,it pulls a bit on the cables and then your adjustment will be off and it will pop off again.Tighten your pull cable till no freeplay,then tighten return cable tight,then back off a touch off the pull cable,and then check it by rolling the throttle full several times if its good then lock it down.Be patient it is sensitive adjustment,I did mine 3 times before I got it right.And lube them up also while your in there.