OK, when you say “a quick yank up and then down on the cyclic” that leads me to think that e might have a nomenclature mixup.
The Collective is the lever mounted to the left of the pilot that controls the pitch of the rotor blades. In very rough terms, when you want to go up from a parking spot, you pull up on the Collective.
The Cyclic is the lever between the pilots knees.
If you are experiencing yaw when increasing collective, that is normal behavior for a tail rotor helicopter.