Clean or change the points. A resistor on a 6V coil with 12V applied is a recipe for disaster, unless you really enjoy changing points- - - -frequently. The proper relationship between battery voltage, coil primary winding, and resistor should give you the following voltage readings:

Ignition on, engine stopped, points closed- - - -there should be battery terminal voltage (12.5 volts or so) at the ignition switch side of the resistor, and 9.5-10 volts at the coil + terminal. Engine running, 13.5-14.5 volts upstream of the resistor and 10.5-11 volts at the coil + terminal. Any higher running voltage at the coil will burn points. Use a "12 volt- - -external resistor" coil to get these readings.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!