I know you don't have any vacuum leaks on that hand built Valkyrie and I know you re-torqued the header bolts.
What do you think?
Could it be running leaner now? You running a K&N filter? Pre filter? I wound up turning out my screws some and shimming my needles. Runs like a monster, no popping, great gas mileage.
Stock filter, I was getting 37 mpg before the change. I will check the mileage this weekend. Popping is not bad, only when I drop gears slowing down. I think it is about normal for the style of mufflers.