Wait. It's a serious problem?! Crap. My engine is running alright. And I was told that a bit of space from the cylinder to the head is ok. Do I just tighten it or do I need to do something else?
that "bit of space" is just due to how it is made, any oil coming from there is bad (note that a leaky muffler can blow oil up there, so fix that first)
They nearly all have a small gap at cyl. to head due to protruding crush ring. That looks like exhaust leak. Should be addressed. Take the pipe off and look across the surface of the flange or put a straight edge on it. It is probably slightly bowed and the edges where the nuts tighten it bottom out before the middle portion can achieve a good seal. In pic. 1 the chrome pipe will seal before the nuts bottom out. In pic. 2 the nuts will bottom out before the black pipe seals.View media item 60786View media item 60785
They nearly all have a small gap at cyl. to head due to protruding crush ring. That looks like exhaust leak. Should be addressed. Take the pipe off and look across the surface of the flange or put a straight edge on it. It is probably slightly bowed and the edges where the nuts tighten it bottom out before the middle portion can achieve a good seal. In pic. 1 the chrome pipe will seal before the nuts bottom out. In pic. 2 the nuts will bottom out before the black pipe seals.View media item 60786View media item 60785
They nearly all have a small gap at cyl. to head due to protruding crush ring. That looks like exhaust leak. Should be addressed. Take the pipe off and look across the surface of the flange or put a straight edge on it. It is probably slightly bowed and the edges where the nuts tighten it bottom out before the middle portion can achieve a good seal. In pic. 1 the chrome pipe will seal before the nuts bottom out. In pic. 2 the nuts will bottom out before the black pipe seals.View media item 60786View media item 60785
If you got a good eye and are confident with tools you can give the ears of the flange a tap with a hammer to make them look like the chrome pipe pictured. You can also put the flange on a belt or disc sander to make it flat. Go slow with the sander to make sure you remove material evenly. I prefer the hammer method, but have used both.