What's wrong of my chains? Gap at sprocket?

what's wrong of my chains?, originally uploaded by achung_123.

My chain has been a bit lose since I replace the rear tire 2 months back. My ride was fine, and I didn't bother it too much since I don't have right tools to deal with it anyway. So I finally got a new torque wrench and right size socket last night to work on it. It supposes to be a simple and straight forward process... but a 15 mins job turned into 1.5 hrs of nightmare...

Here is what I did: losing the axle nut a bit, and adjust the sliding shoes on both left and right and make sure the spindle align... check the chain tension - it looks good; and I re-torque the nut back....everything works as planned - simple, right? Things just start doing downhill when I spin the wheel. Normally when I spin the rear wheel I would feel a constant low resistance; but this time.... there is a spot where I feel something got caught! After close inspection, I found one small section of the chains is not 'fitting' well into the sprocket anymore. I can actually see through the gap!!! WTF?

So... after post my problem on both BARF and Ducati MS, fellow riders suggest that I need a new set of final drive - both front and rear sprockets, and new chain. I have to admit that it is about time anyway - look at how much the chain is stretched. This could be a good excuse to get a new set of nice Supersprox sprockets and RK GB525 gold color chain.

For many experience rider, replacing chain and sprockets is just part of the regular maintenance. This is new to me... and will see how this fix will go. I will post report and pictures once it is done. Stay tune.