If you popped the clutch while you were pedaling around (sorry if that wasn't clear) then the plug should have been black and oily. This makes me thing you have a fuel problem. Are you using the choke correctly? With these style of carbs the choke isn't a separate jet so it can be a little demanding to do it correctly. Try different choke positions.
Is this a used kit? if so I guess it could be the exhaust but I really, really, really doubt that.
Good luck
Is this a used kit? if so I guess it could be the exhaust but I really, really, really doubt that.
Good luck