From the pics it looks like we're dealing with a DT125LC mark 3, and yes the black pipe that's not connected is DEFINITELY the 2 stroke oil feed. Unless you connect it up quick the bike won't tickover, or run at all for long
You need to connect it to the brass stub near the front of the carb (right side) where there is currently a yellowish breather pipe attached. This breather pipe should then be attached to the white plastic stub near the rear of the carb.
I've restored a couple of these bikes and know them well, honest! ' alt='>
I've restored a couple of these bikes and know them well, honest! '>