Originally Posted by chris_wuz_here
hey im 13 and i think i broke my stem on my 2004 f3 haro or my fork ithink its my fork because the top of that big long bolt thing that like tightens the thats in the top of the stem broke off wen i was ridin and it seems loose and i dont no wat to do
It sounds like what broke off was your compression bolt for the headset. This is not related to your stem specifically and you likely haven't caused your bike any serious damage, but perhaps some minor damage.
You will want to get some hex wrenches to do some work on your bike for this and a few wrenches.
Take a look at the 'repairing threadless headset' from the link above, pay special attention to the 'star nut' photos as this most definitely applies to your bike.
The rules for adjusting a headset:
1. Loosen the rear bolts on your stem that clamp it onto the fork. This allows your stem to go up and down easily.
2. Tighten and loosen the bolt on top of the forks. This is the compression bolt.
3. NEVER over tighten the bolt on top of the forks! It causes the star nut to strip, the bolt to break, or other problems.
4. Bike shops have replacement headset parts available and aren't crazy expensive.
5. When you loosen your stem, tighten down the top bolt JUST enough so that the bars/fork does not shake around, then tighten your stem back down. Do NOT crank down on the bolt on top of the forks!!! DO crank down hard on the bolts on the stem that hold it to the fork.