A decent installer will cut the immobiliser wiring back so it can't just be exposed and joined back together easily. Most don't bother doing this, a friend was stunned when I bypassed his Clifford alarm in thirty seconds when it went bad on him while he was out, and he called me to help. Had it been properly installed (it was installed by a Clifford certified installer), I would have taken me ages.
The immobiliser wires should go to two places at least, either ECU, fuel pump, starter, ignition. Check continuity on these circuits, it will be one of these that it causing your issue. You should be able to establish this by the location of the wires you have soldered. Bell them out with a circuit tester, and see which ones are open circuit.
Hope this helps.
2001 RC51 SP1 (modified)
2007 GSXR1000 K6
1994 CBR600 FR (very modified)