So this weekend after an oil change I replaced the regular NGK with 3k on it with an Iridium.
I'm impressed. I don't know if the improvement came from a fresh plug, the Iridium, or both, but the bike has a little more power. There is more pep on the low end and with the throttle wide open. I'll get a surge of power on long hills where there wasn't any before the change.
Great stuff. Thanks guys. I'm surprised.