My adjusting plate is on 4. I have kept the chain lubed and it looks okay to me. I tend to be obsessive about things! Should I just keep what I have until my adjusting plate is at its end?TW200s came with 2 different wheel sprockets. 50T takes 122 links. 45T takes 120 links. If you have anally maintained your stock chain, it and the stock sprockets will be about 25% worn out. You will loose 25% of the life potential of a new chain by wrapping it on 25% worn out sprockets. If you have not maintained the chain at all, it is probably 75% worn out, and wrapping a new chain around such sprockets will reduce the life of the chain 75%. If I was in your shoes, I'd go ahead and keep the stock parts and save for a whole new set.
Disagree. Get rid of the stock chain. After making what seemed like weekly adjustments to the stock chain on my '08 I put a DID Pro V O-ring chain on in Aug 2009 and have not needed to make a chain adjustment yet. One less thing to worry about.