As Gert said ...
It's possible you've glued the magnets wrong, the polarities all have to be in the same direction.
Test the output of the stator buy setting your meter to high voltage (200v AC).
Unplug the stator from the regulator, start your bike and then test the output of all three phases (3 yellow wires) coming from the stator, each should be putting out around 40v+ @ 5k rpm.
Also, without your bike running you can check the stator is a good one by setting your meter to ohms (20k).
Again , Unplug the stator connection, put your negative meter wire to a good earth and then touch the live meter wire to each phase (3 yellow wires) , if any or the tests zero out , the stator has gone to earth, it's no good.