Thanks wilsoac, nice pictures. First, if you look at the small sprockets, you will notice that some of them have lost the tips of the teeth, and the others have angles formed on the tips of the teeth. This is caused by the chain having increased in pitch due to wear between pins and side-plates. The out of pitch chain then tries to modify the sprockets to match the increased pitch, with visible results.
Looking at the larger sprockets, you can see that the chain has increased the sprocket pitch by undercutting the teeth, so they have wide spaces between teeth, and very steep sides of the teeth. As that wear progresses, the teeth will fall off. This problem has been caused by a sequence of events:
1. The chains got dirty and were not cleaned.
2. The dirt acted as an abrasive and wore the pins and side plates.
3. The wear in the pins and side plates caused the chain to have greater pitch between rollers, than the sprockets had between teeth.
4. High localised pressures developed between sprocket teeth and chain rollers, since they had different pitches. Instead of the roller arriving precisely in the valley between sprocket teeth, it arrived on the far side of the valley.
If you remove your chains and hold them side-on, so their pins and rollers are vertical, you will see that there is a pronounced curve in them, due to the slack between pins and side plates.
At this point since all of your chains and sprockets are garbage, it will do no further harm to keep using them until the teeth fall off the sprockets and the chain jumps around them without driving them. The whole set will need to be replaced together, either now or when total failure occurs.
