Re: Chain jammed in engine cog
Sounds like you need a second tensioner coming in from the top to line it up going off your sprocket.
Be sure your sprocket is centered on the wheel first thing - then you want to make sure your chain is properly tight (1 cm - 1.75 cm) and aligned to go from the motor onto the driven sprocket smoothly.
One thing you can do to be sure your tensioner doesn't move is just replace the mounting bolts with steel bolts, then you can torque em down good and tight without worry of stripping em.
I've had it bind at the drive chain - it sucks. Just work it with pliers and a screwdriver and you can get it out eventually. Might take 15 or 20 mins. I've done it on the side of the road before, so I guarantee you you can do it without taking the drive sprocket off.