there is play in my fork
 

so i was cleaning my bike and i was tightening some screws b/c there was this weird craking noise from my headset/stem. so i fixed that but now there is some weird motion going on

if i stand in front of my bike and place the front wheel between my legs, tight, and i grab my handlebars: when i pull the bike towards me fast, there is this weird motion from my fork/headset/stem area. it shifts a bit. is this normal. i never noticed it until now.
help me, i really don't want to die

Your headset's loose. Check out the Park Tool website and learn how to fix it (you'll need headset wrenches).

Ditto... loose headset.. happened to me on my beater, it's annoying as hell.

threadless: http://parktool.com/repair/readhowto.asp?id=65

threaded: http://parktool.com/repair/readhowto.asp?id=127

crap. that's what I was fearing. ok. thanks a lot guys

you have a threadless stem (on your barenuckle) right? It may be that your stem has slipped a little. If there is play between your stem/spacers on your steerer tube at the top of the headset that can also make a thunking noise....