The adjuster bolt is on the outside front of the chaincase. It's that bolt you see sticking out, pointing towards the front bumper. Lossen the locking nut, back it out till there is no tension on it, then turn it in till you meet resistance, then back it out 1/4 to 1/2 turn ( like Avtech said). Snug down the locking nut, without turning the bolt, and then you are adjusted right.
On the inside there is pivot type adjuster, with a roller on the end that contacts the chain. Some times that roller causes problems, and you may need to replace it. Could be the chain too. I'm thinking it still may be a bearing going bad on the jackshaft or on the track drive shaft. We all like for you to eliminate the easy and cheap things first, and only then tackle the pita items, like a bad bearing. One more thing, if you want to take the chaincase cover off ( which I would reccomend, if after going thru the adjustment proceedure, you still have that noise) you will need to take the exhaust pipe and muffler off to get good access. No big deal, just remember where all the springs go.