When you say it jerks, you mean when you click it, it jumps a bit to the left? Yes I see that.
How about that: instead of trying to fix it, can I show you how I would achieve a fully functional menu, from scratch?
I'd use only one symbol I think. And maybe have a different approach. At the moment, your menu won't really work great on phones because it's very high. Way too tall for the landscape phone, and maybe also for the portrait phone. You want your visitors to be able to use your menu very easily. It's important to make things very easy for mobile visitors, with as few interactions as possible.
I'm going to do it and record it as a screencast. Will be back in a few.