Mk ones have a tickler and choke slide. MK11s have a cold start device and no tickler. I have a pair on a twin and they do start it well enough but I much prefer the Mk ones that I've had on the Knight for decades. They start with just a three second tickle on the front, and I never use the airslides. As you tickle you can feel that there is petrol under the float. I have used 930Ls and even a 930R on Comets with no problems. My oversized Comet uses a Mikuni and I really miss the tickler. If there is any failure in the fuel supply you can kick for hours without success. If you run out of fuel while riding and don't hit reserve quickly enough there is no way to tell when the fuel is through. I assume that as the floats rise they reduce and slow the flow and it is hard to tell when it is worth tryint ot restart. I envisage the same problem with MK11s. With the Mk one you can hold the float down and feel it fill. If you do manage to flood a warm engine, it only takes a couple of kicks with open valve lifter to clear it.
If anyone has a Mk one 1034L that is not in use I'd like to buy it for my Comet