Not much luck with the Gunsons Colortune

[Fazerider]

Is the oil on the plugs some you used to ease removal? The one tip we can see looks dry, if very sooty. It certainly looks as if it has been running rich.
Never used a Colourtune, but would expect it to need near darkness for a good indication.
Don’t pull plugs when the engine is running! The ignitor circuit limits the peak voltage using a capacitor, but these gradually reduce in value with age meaning the potential peak voltage generated will increase. In normal use the spark limits the voltage, but if the gap is big it relies on the capacitor to restrict the peak, so avoiding damage to the ignitor circuit/coils/insulation. With a tired old cap the safety margin is reduced. In your example it was the lead insulation that couldn’t cope so you copped a zap..