Wasted spark

If you are running a rich afr, can the wasted spark cause a secondary ignition on the exhaust stroke, resulting in back firing or another unwanted result?

Hi Brett, this isn't actually a concern with a waste spark system. The spark on the wasted side of the coil will occur somewhere near TDC on the exhaust stroke and there should be nothing combustible in that cylinder at that point. If you're running a rich mixture then you will have unburnt hydrocarbons in the cylinder but you'd require additional oxygen to achieve combustion.