I guess this is a question for the old timers that have been around for a while. Back when I was int he business in the early 80s I don't recall having spark plugs be defective or go bad too often. Now it happens all the time it seems. If you pull the plug and hold it away from the engine it sparks across the electrode correctly, but if you lay it on the engine it doesn't spark across the electrode because it is grounding out due to I guess sparking inside and shooting the spark to ground without crossing the electrode. I always thought NGK were the best plugs along with ND but it has been a lot of NGK plugs causing this. It can be hard to track down for the beginning mechanic because the plugs are nearly new when they seem to do this. It isn't just plugs I've installed it's in friends bikes, other mechanics bikes and bikes that people bring in for service. Any thoughts?
