I was a Schucks recently and decided to purchase new spark plugs for my ’72 CB500. They didn't carry NEK D7EA plugs, but the guy told me the Autolite 4164 would work. At the same time I replaced the plugs, I adjusted tappet clearance, timing, synched the carbs, sealed the tank with Por-15, and ditched the inline fuel filter. After all of this the bike ran much better, but would bog a bit and pop out of the no. 3 exhaust. After going over everything, I bought some NEK D7EA plugs and threw out the Autolites, and so far, the bogging an popping is gone. So – my question is whether the man behind the counter was right. Were the 4164s the problem?