I went with an Edelbrock unit on the XR... not really a carb per se... uses a needle for all the metering. With an accellerator pump. The thing absolutely rocks, you can dump it and it won't flood (which is nice for those of us with a big piston and no pink panty button....
But if you get in a pinch I am an old carb tuner from waaaaay back.
Do the Katooms come lean or something? Did you change your exhaust? Free up the intake? Or change something else?