By pucks, I mean your clutch pads, a friction material used to engage the motor to the flywheel. About your head, if it was shot, you'd see residue around the outside of the cylinder under the head. Check your whole top-end for black crud seeping out.
Have a look at this:
And read through Norm's rebuild(note-you don't have to take the little sprocket off to get at the clutch, he just shows how its done)
If you do disassemble, search for "Adjusting Flower Nut" to set that back up properly.
, you could try tightening your flower nut first, That might help, if its just not tight enough to engage fully that would glaze the pads and cause screeching.
Basically, you pull the clutch cover, remove the little lock screw on the 'flower nut'(you'll see why its called that when you see it). Now, with your clutch locked off(handle pulled it), Tighten the flower 3-4 notches and put the lock screw back in and the cover back on. Just make sure the bike will still roll freely with the clutch handle locked on before you put the cover back on.
I should've said that first, but it's always good to know how things work first, eh?