[LONGHAIR]

If you don't get the pressure "balanced" by getting the rear bled, anything you do to get the valve centered is worthless. It will just pop again.

If you are sure that the rear is correct and has no leaks, loosen a front bleeder, push the pedal down, to the floor. At the floor, it should "click" and travel a bit more. This is the valve re-centering. Tighten the bleeder, let the pedal back up and let it sit for a few minutes.
Check the fluid level in the master cylinder, fill if needed.
Now open ALL of the bleeders and let them trickle. Keep an eye in the fill level of the master cylinder, do not let it get low. Let it flow for a while, this will flush out some old fluid and any air left in the system. This is known as gravity bleeding and it works very well, plus it keeps everything balanced....not re-popping the valve.

ETA:
To address the original question.
Yes, there is an adjustment. The link rod that goes from the pedal into the back of the master cylinder has a threaded adjustment to it. Just be sure that you are "just taking up the slack", you don"t want to actually put pressure against the back of the plunger.
If this doesn't fix it, you probably have a master cylinder problem (internal leak)