Re: Locked UP ???? Help
It's a little hard to tell from the photos but it appears your chain is very tight. You want about 1/2 to 3/4" of slack in the top chain with the bike pushed forward against engine compression. Also check the alignment of the tensioner wheel with the chain. You might need to twist the bracket slightly to get it to line up with the chain path. Does the tensioner wheel roll easily, does it rotate when the chain passes over it? One very important thing you should do is secure the tensioner bracket to the frame so it can not loosen and rotate into the spokes. You can use a self tapping screw or drill through the bracket and frame and install a 10/32 screw/bolt with nut, but get the alignment right first. Everything else looks okay and I see no reason for the chain to come off except for the items mentioned above.
As for the engine not starting you still have not said if you've confirmed you have spark at the plug. I read where you said you checked the wiring but that doesn't mean the plug is firing. Please check this and make sure you have the proper fuel/oil mix and have cleaned the carb. It might be full of oil.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"