poison,

"Wobble" is kind of a general descriptor, but I'll give you my two cents worth based on what wobble means to me.

If the three links connecting the servos to the swash are too short, the main blades will have too much positive pitch
for the rpm, the head speed.  The blades will be in a semi-stalled condition.  The heli will wobble and bobble and make
noticeable chopping noises.

If this describes your situation, the cure is to lengthen the swash to servo links.  1/2 turn makes a difference.

If by wobble you mean a vibration in the head, i.e. when you look down on the screw holding head button  you see "wobbles",
then the main shaft is probably bent.

Hope this helps.

JEM