Thanks to everyone here for the helpful pointers and to Gordon who gave me a bunch of info over the phone. The bike is running strong through the entire RPM range now and the CR carbs seemed to be dialed in well with the needle set in the middle, 115 mains, and 3/4 turnout of the air screws. I still have to sync the carbs and I'll do that when my Morgan carbune arrives. The bike feels very strong and I brought it up to 5k a couple of times but I'm going to go easy for the next 50 miles and then take it up a bit higher. No more white smoke. I tightened up all of the clamps on the intake rubbers and that might have been the culprit there.