I have the chain off while making some mods and then left it off so I can rev the engine and check the jetting. Two questions:
1) Is this just the reverse box or does it do something else?
2) It makes an awful racket while revving the engine. Can it be greased? I don't see any grease fittings or oil ports, but I thought I saw a post that you an take one of the bolts out and squirt oil in it.

Is there any way to oil this?

Thanks.

yes you can pump grease in it from a grease gun.
i do it all the time to mine.you can take the 2 bolts that hold the plastic guard on out and use those holes they should go all the way through.i use a constant velocity joint grease end on my gun.
those bolts look bigger then mine so you might just be able to hold grease gun end tight to holes and pump grease in it.
put plenty in it you have 2 bearings in it one on end where the nut goes and one just out from the sprocket,inside of course.
i think these gearboxs get over look a lot,it will definitely shift slicker and do better

pud