<VV> Assistance with a carb problem

[John Kepler]

A look down the RH carb shows the venture cluster dribbling gas which I'm
fairly certain is the source of rough idle and the backfires. There is no
such dribbling out of the other carb 

First, it's "venturi" (not to worry, your likely spelled if right and your
spell-checker probably changed it on you....mine had to receive an
electronic slap in the head to stop doing it!).

Second....check your carb synchronization.  "Post-nasal drip" from the
"low-velocity carb" is one of the indicators.  I am a bit puzzled by your
"rusty" comment though....even a turbo is carbureted.