So, I'm doing the 20k service on my FB and on the screaming eagle plug box it says they are pre gapped at .35? I thought .40 was were they needed to be at? Should I change or leave at the .35?

 

For what it's worth, I was "taught" that today's hi-energy ignition/coil systems allowed for a slightly wider plug gap, which yields a slightly longer spark, which results in more complete burning of the air/fuel mixture in the chamber. So for years I gapped my plugs at .040"-.044" on my old FXR and never had any probs, and do the same now on my FB. Others may differ, and of course, your results may vary!
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Thanks, I just changed the gap to .40. I'll take her for a spin and see how she does. I wonder why they come pre gapped at .35?

 

So, how did it do? I was wondering the same thing, and gapped the plugs at .40 and feel like I may have lost some power. This, of course, could be my imagination or be caused by something else. So I'm curious how it turned out for you.

 

When your plugs get over a certain age the gap will have expanded anyway and I never notice any improvement or loss of power when I buy new ones. She just runs and runs and runs!