timing light adaptor
just like barrman says,use anold car spark plug wire,your timing light induction clamp will clamp right on the car plug wire ,and you dont need the spare battery,ONLY CONNECT THE POSITIVE AND NEGATIVE CLAMPS FOR THE TIMING LIGHT POWER TO THE DRIVERS SIDE BATTERY POSTS ONLY,IT IS ONLY 12 VOLTS,IT ONLY BECOMES 24 VOLTS AT THE POSITIVE SIDE OF THE PASSENGER SIDE BATTERY,HOW DO I KNOW THIS,I CHECKED IT WITH MY VOLTMETER,THIS APPLYS TO ALL 24 VOLT SYSTEMS USING 2 12 VOLT BATTERIES HOOKED IN SERIES,so be careful,most timing lights dont have a very long cables, so just make sure you dont get it caught in the fan belt,voice of experience on this,good luck to all on their projects