i think my crank is going bad

not to sound stupid but you sure it isn't something on the bike like the exhaust or something bouncing around?

I dont really know much about these little engines, my experience is in the automotive world so I am not much help here. sorry. lol
 
They transmision gears will be on the right. So when you take it apart you tip it on its right side. I have to do this to. I have a nock so I am going to replace the crank bearings and putting a 3mm crank in it. good luck.