Question about dual fire ignition.

[SCouch]

I read in another thread about dual fire ignition.  I was curious about this after replacing a pickup coil and going thru the electrical system.  I always thought that dual fire was 2 sparks close together for better fuel ignition.  From what I gathered while checking out the system on my 2000 Monster, this system fires every TDC rotation of the crank.  This means there is a spark between the exhaust and intake strokes.  Am I confused, never run across this before.

[Howie]

You are confusing dual spark and waste spark.  In a dual spark you have two plugs in each cylinder that may fire simultaneously or a few degrees apart.  Your bike has a distributorless ignition system for both simplicity and accuracy, rather common on cars and bikes.  Cars, usually having four or more cylinders firing at even intervals use one coil for two cylinders and fire once at the power stroke and once on exhaust  stroke.  Since spark on the exhaust stroke doesn't accomplish anything it is often referred to as waste spark.  Since your bike is a 90⁰ twin two coils are used, but the same principle, one spark on power, one on exhaust.