I want to see you get a knee down...maybe not, no crash protection.
Your rear sprockets don't look too bad, but I'd take you chain off and give it a good clean with kero .
There should be a joining link on it which you can push out the pin and break the chain. You can buy replacement pins from a bike shop (the old pins are an absolute bitch to get in there once you have removed them).
Knee down hmmm.. after 8 years I think the tires are near perished.. I was going to put a face mask on to pump them up. These non motorised bikes turn like a blow fly!
I was thinking about rigging up a two stroke engine onto this thing.. I've seen one before.. how hard can it be?