My new to me bike is running poorly. Wont kickstart(have to jump it), has a huge hesitation, and pops off throttle. All leading me to believe it is running lean. Now how can I fix this? I tried the adjustment screw on the bottom of the carb, and whether in or out and everything in between it still ran horrible. Mods: Full DR. D exhaust Swiss cheesed airbox Boyesen acc. pump bowl I cleaned the carb, reset timing, checked valves, and did an oil change/spark plug swap and it got me nowhere.