Well I'm gonna upset the apple cart here and say that I don't like CR's. There, I said it and I don't care who shouts me down. I bought a shiny new set of 29mm CR's for my K1 with it's hotrod 836cc engine, JMR stage 3 head, Megacycle 125/75 cam, etc etc, and it ran like #$%*.
I tried every needle position possible and I just couldn't get it right. And the stupid idle screw arrangement that you can't access without removing the tank is just dumb. (how handy is that? You gotta remove the tank to adjust the idle?)
I took them off, installed a freshly rebuilt set of original carbs with one of Brian's (Tintops) filtered stacks setups and bigger mains, and it runs better than it ever did before. Not as cool as CR's, but it worked great. If you could find a good set of Mikuni 29mm smootbores I'd use them, I had a set of 33mm smoothies on my 1100cc Suzy Drag Bike and they were easy to adjust, had a proper idle screw position and worked very well indeed.
Of course, the 32mm CV carbs on my Gold K2 are superb, well matched to my 836cc engine, ultra light throttle, no flat spots, light weight and better fuel economy that any other set up. (not that it's a priority, just a benefit) The carbs were common, I believe, on several later models (including the last of the 650's I think?) but need to be re-spaced to fit. Definitely worth the effort, and would be my first choice if I had to do it again. Cheers, Terry.