After struggling with the pumper carbs (several) on my RTS and still not getting it to start or run correctly, I gave up. I flipped the manifold and mounted a 34mm mikuni round slide carb. That caused problems because the carb ran straight into the shock crossbar. Well some bending, cutting and welding later I have room for the carb. It starts and runs well (still doing some jetting) and I got some other things done too.