things are a bit clearer now-I always say that before sticking my foot in mouth. the expelled fuel over flow is coming from the slop drain( or the fliptop cover), isn't it? clearly the main tank enjoys an elevated operating pressure. ( surprisingly this is normal and part of the design of the bike)- and by extension the sub too! end result is that the gas is blown out the sub and into the slop drain -and if i'm right about that, only rerouting the subs vent line INTO the main will fix it.( i'm not sure if routing to the lower part of the main will do anything for you, except to drastically slow down refueling stops.) this would be the exact same thing I ran up against. piping slightly different, but same problem. if you can't insert a vent into the top section of the main, then you might have to silver solder a tube that goes from out side bottom(hidden from view)- thru the tank to someplace reasonably close to the top. I believe you mentioned that the vent line is an AN#6 this would be the time to make the sub's vent bigger, as well.
the_gr8t_waldo screwed with this post 07-07-2013 at 12:52 PM