One more hint.
If their is a bit of play in the stem dont just tighten the bolt up on the otherside from the hinge to try and get rid of it.
You will simply trash the threads.
Its a tad more complicated than it appears. You need to loosen a couple of grub screws first other wise it doesnt do anything then tighten. That bolt up and retighten the grb screws. Its in the manual which is downloadable.