so the tensioner isnt working??? i look at the other photo and my the looks of it, take a few links out of the chain,and it should give it enough tension to ride. ive done that countless times. If that doesnt work, up the back cog up 1 tooth. it may be the exact gearing you wanr, but it will work. and if that still doesnt work, slap a old mech. on there, and mess with the adjustment screws so it lines up with your chain line.