"A friend purchased two Honda Express (early 80's?)motorbikes. One doesn't run for more than a few seconds on starter fluid. Good spark, clean carb, vacuum fuel tap working. No fuel appears to be entering the cylinder. There are several ""mystery"" vacuum tubes leaving a ""box"" on the cylinder head. A fitting on the back of the airbox and some sort of ""dashpot"" on the way to the carb are also involved. Is this some sort of automatic enrichener/pollution control? How do I trouble shoot it? I only have a few days as they are leaving on a vacation with the intent of riding the bikes. No one near St. Louis, Missouri appears to have a manual."