A good old immobiliser question-speed fight 2 - Help Plz!?

Hiya People,
Im struggling with this one: Speed Fight 2 (03 & 50cc)

Ok, for some reason my original immobiliser got toasted, so like many others before me, I went straight on E-Bay and bought just the CDI 100 (ACI100) bypass immobiliser, fitted it, no start, gutted.
It sparks, but obviously I have no idea if the timing of the spark is correct etc & turns over like a trooper.
Do I need to replace the lock set too? or am I missing something? the scoot came with one black key & started fine before I got into this mess.
Thanks for you help peeps,
From Chris in sunny Wigan.