Jetting
Look at a 2001 600 rmk. That was a big block 600 with flat slides. Base set up on that was 0.6 air jet, 40 pilots, 310 mains, 2.0 cutaway on the sliders, J8-8BEY01 needle, 145 starter jet. Those carbs came with a pressed in needle jet and were stamped on the carb body. Hope the one you got are the same as the 600.... Parts list does not say what the 600 was. I think the 800 were P-8