Re: (Motorized Bike Kit) Good Chain Tension Setting rear sproket
1/2" to 3/4" of slack. The rear sprocket must be centered on the hub or proper chain tension can never be achieved. I'm not a fan of spring loaded tensioners. They allow slack in the chain when you least want it.
Make a pointer that is attached to the bike frame. Suspend the rear wheel so it can be spun freely. Aim the end of your pointer at the outer ends of the sprocket teeth, spin the wheel and you'll quickly see which direction the sprocket needs to go to get the teeth concentric with the rear hub.
I use a plastic head hammer to tap the sprocket, hitting on the teeth to move it. If you don't have a plastic hammer try a piece of hardwood or something similar to protect the teeth from damage while tapping it into position. Or, as will be suggested, purchase a sprocket adapter in place of the kit 'rag joint'. Good luck.
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