I just got the metal seals off the mixture screws and thought I would share the tecnique. I first used an awl to impress a small dimple on the little covers. Since you can't reach them at right angles the drills tend to skate off and could damage the carb body. After dimpling them I used a 1/16 drill bit in a pin vise and after about 5 minutes of hand turning I had a small hole. I then moved to a 1/8 bit and enlarged the hole. I put the tip of the awl in the hole and rocked it back and forth slowly until the cap popped of exposing the mixture screws. Now if I can pull the breather hoses off I'll finish marbling, adjust the mixture and if it warms up a bit, mount the V&H Cruzers. I hate Winter.