As I looked at the voltage drop on my VOM, it showed me that my theory was correct. I jumpered out the regulator and all functions are now normal down to 3.8 volts, at which time the pic chip's internal brownout detection takes over and powers down the chip...
I am getting almost 3 hours continous running time now without a problem, on a 700 mah 4.8 volt nicad pack! Excellent performance as far as I am concerned..!
All I did was jumper the VR out of the circuit altogether, which eliminated the dropout problem.
T106d is a 400 volt-4 amp unit.
TIP42 is almost a direct substitute for the BD242 which I did for the fact that I can buy it at Radio Shack. I think the Hfe on the TIP42 was a little less but it functions well in it's environment.
Doing the 2 changes I made to the CDI board itself concerning components was to substitute a TIP42 for the BD242, and a T106d for the BT151...current consumption dropped from almost 900 mah to 300 mah with this change on one of the 4 boards. Maybe I should change all my boards? Voltage regulation doesn't seem to be needed.