Mates NC30 having problems starting and was suggested that CDI unit might be cause of the problem. This evening, substituted unit off my bike onto it and started first time. However, after about five minutes of running bike cuts out and unable to start again. CDI unit boiling hot. Put back on my bike to check and sure enough, it's gone. So the question is what would be the likely cause of the problem on his bike?
And does anyone have a CDI unit going cheap?? lol

most likely the reg/rec is gone and sending voltage spikes into the circuit, check/replace that before frying any more cdi's