I finally found the issue with the cheapo scooter. Turns out the previous owner didn't use a torque wrench to tighten the nut on the crank shaft. It got loose and ended up destroying the entire crank shaft. Only thing you can do now is to replace it. So do yourself a favor and when you Tinker around with an engine get yourself a torque wrench. Sure they can be a bit pricey but they will save you from a stupid situation like this.