Hi kksiu2002:

RCEXL current ignition must be used to a MAX 6.0 V full charged battery. You can damage the ignition if you are using a 5 cell battery.
Also , when you are using the RCEXL ignition, have you tested properly the static ignition advance timing angle ? The magnet diameter and sensor housing has some influence on timing advance.
I've mounted the RCEXL ignition on many engines, including XYZ brand . Also to replace original and expensive ignitions for DA, 3W, Zenoah, Kroma, ZDZ, MVVS (Evolution in USA), RCGF, CRRCpro , single and twin cylinder. Also on glow to CDI conversions (gas and methanol fuel) on OS, Saito , ASP, JBA, YS Yamada, in many sizes, from 0.51 to 1.80 .
All of them are great runners, easy to tune and performs awesome. All of them have been checked to set the ignition advance to 28º BTDC. Some of them works better at 26 and only one works better at 32º BTDC , but all advance measures are taken with a ignition timinig kit , a device to check with a led and a buzzer when ignition time occurs.

About XYZ blue ignition ........ Some last more than first hour of running time. I've decided not to work anymore with this ignition. Many people with XYZ engines has some burned units ..... They are cheaper, but IMO , the quality is lower than RCEXL.. Current RCEXL ignitions have the plug wire shielded with carbon added to metal shield, the sensor wire shielded and protected, a rpm output wire, nickel plated ABS case , the shrinking tube is adhesive , it has a collar on rear side of plug cap, boot is silicone made .... and more .....

Regards