I built a yugo on a tapco flat. everything turned out nice. I installed a tapco g3 trigger group. When dry fireing and cycling the bolt with the trigger held. the disconector does not catch about 25% of the time. It seems like the bolt is not pushing the hammer down far enough to connect with the disconnector every time. I tried the origional fcg with a semi disconnector and everything seemed to work. The hole in the disconnector is larger than the trigger hole which lets the disconnector ride a little higher. Using the origional fcg I put 50 rnds thru it without any problems. I didn't like the slop in the disconnector that came with the origional fcg so I made a bushing for it. When I tried it with the bushing I had the same problems that I had with the tapco trigger group. Could I grind the tapco disconnector catch a little higher and solve these problems? Should I use the disconnector with the oversized hole? I really apreciate all the help from the AK Wizards out there. You guys and girls? have been lots of help.
Well, its unusual for the bolt carrier not push the hammer down far enough. Usually it is the other way around. Must have something to do with the way you put a Yugo on a Tapco flat.
But to answer your question, yes you can file or grind on the disconnecter hook so that it grabs the hammer at a higher level. Most guys are reluctant to tinker with the FCG, but an AK FCG is very tolerant of tinkerers. I have done what you describe, but for different reasons.
It is hard to describe without pictures, but I would take material off the underside of the hook (where the disconnecter contacts the hammer). The thing to watch out for is to not go so far that the disconnector holds the hammer so high that it cant transfer reliably from the disconnecter to the trigger hook. If that happens, the rifle will fire when you release the trigger. Obviously not a good thing.
If at some point you don't get enough engagement between the disconnecter and the hammer, you can file or grind off a tiny bit on the underside of the pointy part of the disconnecter base where it contacts the trigger assembly (forward of and on the opposite side of the pin from the disconnecter spring).
Hope some of that makes sense.