No head gasket?

So I noticed that when I start up my bike, the idle starts racing until the engine warms up a bit. At that point, it clams down, but to the point where the engine stalls when it returns to idle after revving the throttle. I figured it was running too lean, so I moved the C-clip on the carb needle higher, and now it seems to work better. The idle still races at start, but once it calms down, it runs perfectly fine.

However, I figured there was a leak somewhere, and looking at the cylinder head, I noticed a narrow gap between the head and the jug:



Here I am putting an X-acto blade into the gap...it is a VERY narrow gap, but it's still a gap. Then again, the air leak musn't be very big if it still runs well with a higher carb setting. The black gasket material present everywhere else is not there either, just a (warped) metal plate.

Is this normal, or should I take off the head and put down some gasket material? I tried tightening the head bolts, but they seem pretty tight already.

Edit: I looked at replacement head gaskets on ZB's website, and they're made of metal, so I guess it's right. Still, should I be able to see a gap in there?

Nope. Seems pretty fine.

Awesome, so any insight as to why my engine races when I just start it? I tried spraying some WD-40 on the intake manifold to see if there was a leak but I didn't see much, what should I be looking for?

Heh, funny thing is I was using too much oil before (16:1) and just leaned it out (24:1). The problem is the idle is only high for a minute or so, I just need to rev the throttle a bit and it settles down to a nice purr.

Edit: Turns out it was the throttle sticking. Thanks for the help =D