I just picked up a Daewoo K2 and the gas adjustment is very stiff. I think it's just fouled but don't want to mess anything up. Can someone who has one tell me what the settings are, whether they should be hard to move and how to remove the plug to clean it? I really like the rifle just want to know the in's and out's of it before I go shoot it.

Sounds like you're guess is correct and it's gummed up.

There are four settings.

"O" =zero, closed, no gas going to the cylinder, used for launching grenades.
"L"  =large, oversized port, reserved for use when more gas is needed, such as a dirty weapon, fouling, or lower pressure ammo.
"M" =medium, standard sized port, and the normal position for firing.
"S" =small, undersized port, used for when the rifle has extra gas energy, such as extreme heat, or higher-pressure ammo.

When you're looking at the gas regulator so you can read the letters, you'll notice there's an arrow on the front sight base above the regulator.  That's the arrow you use to line up the letter for the setting you want.  

To remove the regulator, push in the regulator button and line the button up with the arrow (the side of the button you press in, not the side that has the retaining clip).  Then pull out the regulator.  Unlike the FAL there is no spring tension pushing on the regulator, so it won't pop out on it's own.  You have to actually pull it out.  NO TOOLS ARE NEEDED! (aside from possibly something to push the button with, but I've never needed anything) If it's stuck so bad that you can't pull it out by hand, post here again and ask, or IM me and ask, before you try pliers/crowbars, etc.

It shouldn't be hard to move really.  Same as a FAL's regulator if that gives you an idea.  Don't loose it either.  You'd have a hard time getting another.  Also when you put it back in, make darn sure it's set on one of the letters.  Because it doesn't have any spring pushing on it like the FAL, some people leave it accidentally unlocked and launch it downrange when they shoot it.  Make sure it's set on a letter when you replace it.

There's a yahoo group for the Daewoo rifles at: groups.yahoo.com/group/DR200/.  It's worth signing up for, as there are a couple zip files with the owner's manual, and dispite it's dead look, there's actually alot of high quality infor about the rifles that gets exchanged.  They're also far more likely to know about anyone making parts, or any parts available as well.  

Thanks for the info. It is pretty caked with carbon. I had to use a cleaning rod to tap it out from the back end. Looks in good shape though, just dirty.

Are the barrels on those things Chrome lined?  My buddy has one he was wanting to sell me, but I'm really not interested...  Just curious.

Mine says it is. I don't know if all of them are.

Quoted: Are the barrels on those things Chrome lined?  My buddy has one he was wanting to sell me, but I'm really not interested...  Just curious.

Yup, they're all chrome lined.  The K2, MAX-II and AR-100 (all the same gun, just different importers) have a 1 in 7 twist.  The post-ban DR-200 has a 1 in 12 twist.

As far as quality goes, they're as good as any USGI spec M16 barrel.