Sprocket issue

[shelbycole1180]

How do I stop the sprocket from sliding. Chain pops off

 

[Hellion]

Can you show us the loose sprocket?

 

[Whitetrashrocker]

Did the set screw fall out.
Look up lock collars.

 

[Denny]

Look up split lock collars. The kind that are split on both sides.

 

[bullseye670]

Sure sounds like the sprocket set screw isn't tightened down or it's missing.