I found this method before i found the commonly posted method by Fred or by one of the "don's" around here.. Ohio or P ?
anyway, it's a little simpler than hoisting the frame from the ceiling but it does require some preparation.
The engine has one large pivot bolt holding it to the frame. If this bolt is removed, and the center stand is retracted, the engine and swing-arm assemble will swing (fall) down to the floor. At this time you can unscrew the 4 reed valve body screws and remove the carb-intake manifold as a unit.
There is no need to support the bike.. If the front tire is straight ahead, it will be (precariously) balanced while resting on the muffler.
There are a couple caveats. Firstly, some of the cables and wires are not going to allow the motor to just drop. You have to detach the decompression cable, the fuel line, the throttle cable, plug wire and other wires and perhaps the rear brake cable. (and there may be others).
Here's the trick that makes this easier than the other method (using a rope from the ceiling) :
When you lift the motor back into the frame, don't attach any cables or wires or anything ahead of time. Wait till the motor pivot bolt is in there .. _Now_ route your lines and cables. Route them so that they _will not interfere with lowering the engine the next time you do it_.
The next time you need to get the carb out, you won't need to detach all that stuff, except for the throttle cable (unless it's about 4 inches longer than the stock one) and decompression cable.. the fuel line is probably already long enough to not require detaching it. Route around things instead of routing through things wherever possible.