When I purchased my bike a few years ago it came with a marzocchi z1 fork and an azonic shorty stem. I was able to remove the stem once by twisting and wrestling with it but now I can't seem to get it back on short of hammering it onto the fork. What is the best way to install and remove this stem, or would it be more convenient to buy another stem?

Undo the pinch bolts, and it should slide right on, or off. Tighten them and the stem should stay on.

remove the top cap

The reason this is a problem because both pinch bolts and cap are removed. I've read a few reviews that said this stem was pretty tight on a few forks and I was wondering if there were any suggestions on what to do in this unusual case