so the number 15 bolt which i assume is called the steering stem upper bolt or whatever just randomly snapped off on me while i was riding. I heard a loud pop and almost soiled my britches then i saw this little sob just sitting in the stem neck between the gas tank. my question is that if i were to just drill out the broken part would i have to disassemble the upper triple stem or anything just to put a new one in?

You might be able to get it out without drilling. If any of it is coming out the top you could probably get it out with a vise grip. Also try to see if there any play in the front end. If you brake and push back and forth then you might have to rebuild it because things are out of place. Or you could just install the new bolt and realign the forks.

Of you need to drill it out get left hand drill bits. And start small and work up to largr bits. The lh bits drive the bolt or as you drill, instead of deeper.

Never had the need to do this on that bolt but i would take the steering stem apart exposing that leftover bolt(by diag it looks to be a fair bit)....i would then cut a slot with angle grinder on top of said bolt(thin blade) or use a hacksaw/etc,then use an impact driver with straight bit.

PS...try the easier vice grips method first. 
BTW...any ideas why it broke?

Angle grinder thin blade.... ask for stainless steel type.. they are thinner than standard discs 

Oh that bolt is huge, like a 10mm shaft.
I'd take a nice long rod and put it upward from the bottom side of the stem and give it a good sharp tap.
And soak it form the top with pb blaster. And see if you can get that to come out the bottom.
Essentially it may be stuck there with rust.
Then drill it out with lefty drills, or try an easy out.
Did it break off at the threads, or
Its not affected with steering movements, its pretty much tightened down and it stays that way till the next time you have to take the triples off.
Cool.
Buddha.

+1 for PB blaster 

If you have access to Aero Kroil, try that instead of PB Blaster. The absolute best penetrating oil is a 50/50 mix of ATF and acetone though.

Dremel with a small cutting. blade, did that just yesterday to insert steering lock pins into my tr6.

so with time off work for the rest of week im going to try and get to it tonight or tomo. the bolt broke off literally where the threads start from the top, so its down inside the top triple a bit. I have no idea how it broke off i was coming to a stop light and heard a loud pop. looked down and the bolt was just sitting there in between the gas tank and the neck. if i hadnt had seen the bolt i might have kept riding thinking that something just hit the bike from the road debris.

Im just going to try and drill it out from the top at first and if it gives me any struggle im just going to tear apart the top. i will post up some pics in a bit.

I've seen people welding a piece on it, and use it to loosen the bolt (usually a similar sized bolt, or smaller nut).