I've stumbled across yet another rigging problem with my character...

I've got my character set up and (more or less skinned) - although I have a problem when I try and rotate the neck control in the y axis...

the gums move outside the head!!

I think it's something to do with the cluster I made for it. I don't think its constrained properly

Could someone take a look for me? I'm really stuck....


Thanks

James