... what is the proper plug gap on the 2010 Fatboy lo with stage one kit, they tried to tell me it's pre gapped but it never was with my 01' springer- anyone?

 

Seems to be the question of the week.

Unless there's something specifically different with your Harley it's always been 38 to 43. Typically you just need to check the gap and typically it's where it should be right out of the box. (others may have had different experiences but I always check and for years now have never had to re-adjust.)

 

A while back I decided to pull the plugs in my '96, just to see how they looked. I was surprised to find the front plug gapped at .025 , and the back at.035. It started and ran fine gapped like that. I was thinking about putting them back like they were, but gapped them to .038. Bike ran the same. So I would run plugs gapped anywhere between .025 an .040, my bike doesn't seem to mind.,,