Check the voltage of your battery when full charged. Some users of xyz blue ignition has burned it on a direct usage of a full charged 5 cell NiCD. Or use a 6V regulator.
On the hobbycity customers reviews of this product , many of 'bad' opinions has been deleted.
All engines manufacturers have the faillure rate about their engines / parts. Also about ignitions. Ask xyz ......
Maybe on last production , they have improved the cdi ...... XYZ manufacturer know this ....

Regards