jets

anyone recognize these twin pipes? I bought them from someone that had them on a zr 580. I would like to know what rpm they run at. Or any technical information would be great.

Looking to jet my summit, usually running between 6000-8000 ft. It still runs up there, but not enough to do anything, literally. My brother quotes "A friggen Bravo's got more power than this thing." haha. Just curious as to what others are running and around what elevation, and if you have tips...

I am about to install my new 860 from RK Tek. A lot of people question Kelsey's formula for putting in smaller jets. (480 down to 460) has anyone tried this or are there any opinions out there?