Can someone tell me what this is? It's right next to the crankcase and it definitely doesn't look stock.

 

Looks like the APE replacement Cam Chain Tensioner.

 

but I call it "bob"

 

A.P.E Manual Cam Chain Tensioner- leave it, it's your best friend.

 

awesome. thanks guys

 

+1000

 

Yup, Everyone is correct, Except no ones said to tighten up the locking nut. You want the 2nd nut to be right against the other to "lock" them so they cant loosen up by themselves

 

so tighten it all the way down? any torque specs?

 

That's not part of the installation instructions that come with the tensioner, and I don't think it's possible anyway - I just went and looked at mine, the nut on the end is drilled through and has a pin through it and the tensioning bolt, to allow you to adjust the bolt's tension with a wrench.

Just found this image of what the pin looks like.

 

The nut locks the bolt so it won't turn. It should NOT be against the bolt head. If you have never adjusted a manual tensioner my advice would be to have someone show you the correct way. Over tightning will cause chain failure and major engine damage.