Hi I received my new 80cc china girl about 3 weeks ago and been finding flaws in the kit set up the chain master link catching the cheap plastic roller on the tensioner and popping off, a spring loaded tensioner with a metal gear should be the fix and I eliminated the master link looking for a tensioner and gear. But now my problem is while riding the bike started vibrating bad the the motor shut off instantly and a link in the chain snapped. I fixed the chain and get the bike going but still vibrating and stalled and did that a few times then the motor locked up let of the clutch and the back tire skids. Now I took out the spark plug and tried turning crank with ratchet and the motor wouldnt budge forward so I tried to turn it backwards and it moved and it blew my brothers thumb off of spark plug hole big time. Can a clogged muffler baffle cause that super compression and lock the motor?