Motorcycle Repair: Single Fire Iginition Coil vs. Double Firing Coil ?, fire ignition, double fire

Question
Hi Gary

Its me again (the newbie)

My m/c tech tells me its would make my '85 FLHTC Harley run much better and eliminate the electric problems I'm having.

Gary can you help this ol' man out by please explaining to me just what's the difference between the Single Fire Ignition Coil I'm having him install and the Double Ignition coil that he is replacing.

That darn Single Fire Ignition Coil is costing around $400 bucks !

What makes it that good ?

The only thing I know Gary is that an inanition coil sets-off the spark that sets the gas off in the cylinders.

Please explain this to me Gary,so an ol' fart like me can understand the workings of workings of both.

Thank You Gary
Ray M. :-)

Answer
Ray, Ill try.The double fire coil usually fires the plug with less voltage but it fires the plug before TDC and after TDC  to get a better burn on the fuel mix. The single fire coil hits with more voltage and does it once before TDC eliminating the drain on the ignition system. Its supposed to provide a more precise throttle response and help improve EPA emissions.