Re: Air in lines/carb issue?
What probably happened was the tensioner bracket rotated into the spokes. That is one of the most common mishaps to occur with a new builder. That bracket must be mounted securely so it can not move.
As for the sprocket attachment to the rear wheel, did you install it correctly? It must be a sandwich. Sprocket, rubber, spokes, rubber, metal 1/2 moon plates. If the sprocket was against the spokes that is wrong. Much has been written here about proper sprocket installation. Do some reading, keywords, 'rag joint install'
Also chain/sprocket alignment and chain tension are critical. There is a lot of information here on those issues. Search and read.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"