Did you re-adjust the voltage regulator when you switched back to the 6V? You might be putting somewhere in the range of 9.5 volts into the 6V battery, depending on whether it was set up properly to charge the 8V battery originally.

Yes, if a charging system is set up right when the 8V is installed, it will shorten the lifespan of light bulbs and ignition points somewhat.
Jerry


"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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