First off your Jawa does not have points or a condenser it has electronic ignition. You mentioned that you had cleaned the rotor with carb cleaner and sand paper. Did you get any of the carb cleaner on the coils surounding the rotor? If so you may have stripped the varnish insulation off of them. You said that you have spark. Did you test this just by laying the plug against the cylinder ? If so that may not have been enough. Do this instead. Remover the spark lug cap (the Jawa does not use a supressor cap) then with the spark plug still installed hold the spark plug wire about 1 mm away from the spak plug terminal and crank the engine. You should see the spark between the wire and the plug terminal. That is the best way to do it because it takes into account the added resistance that the engines compression will add. The best to check for the float is to place it in very warm water and hold it under for a while. The warm water will cause the air in the float to expand and any rupture in the float will easilly be visable as the air bubbles escape from it.