I have a 01 wolvy with a cold blooded starting problem and when you lean it out it tends to stall or hiccup. Before I leaned it out it would backfire through the carb into the air box. I have heard you need to rejet, but that seems unneeded without mods. Any help would be greatly appreciated.

 

Mine used to do this until one day I was riding with shorts on. When it "hiccuped", I felt the rush of air on my leg. It turned out the rubber mount between the carb and head had a small rip causing the lean condition.