Very interesting project. I was looking for others that had built v4 choppers and came across yours. If you are interested you can see my just recently finished v4 chopper on the VFR website also. Goto:http://vfrworld.com/forums/mechanics-garage/30574-misfit-quadzilla-finished-photos.html
The rubber hose on the back side of the carbs? Need to be more specific. Where is it coming from on the carbs?? It could be the float bowl vent. Or is it coming from the air filter box? "Second, the rear coil, which lead does the yellow wire go?" When you say LEAD, does that mean wire going to a spark plug? The yellow wire usually goes to tachometer. Just need better info. One set of coils is the front coils and has a blue wire and a black wire. The rear coils have a black and a yellow wire. Just look in your shop manual at the wiring diagram. It is all laid out for you.