Yak,
If the 42T pulley is not supported as you are tightening the through bolt, you will get vertical wobble. So.... as you are tightening the bolt make sure you are supporting the pulley but not putting any vertical load on the pulley. Please see illustrations and related videos. Notice B runs completely true but A and C have wobble.
A. Hold the main shaft, tightening the screws. A video can be seen from the slight swing 42T.
B. Hold 42T, tightening the screws. you can see from the B video did not swing 42T.
C. Like the picture C, the 42T side to put some force (F), tightening the screws. As you can see from the video C 42T serious swing.
Bare with me, I am trying to download the Vid's. But untill then it's not that the Pulley is warped it's the way it is being tightened.
Kevin