It has what appears to be good spark. With plug cap off will shoot 3/4" to ground. Good compression on all four cylinders. (4,500 miles on bike). This one is making me lose my hair.The fact that it fires up all be it with starter fluid and you swapped out the IC for another one with the same results confirms the IC is good, Do you still have Spark ?
Or has it lost Spark since it made that noise ?