1) The bowl drain is loose on one of both of the carbs and is leaking. Pretty easy fix- just get to the carbs and tighten the bowl screw.
2) More likely problem- you have a bad base gasket that is allowing exhaust gas out at the base of the cowling. That gasket seals the exhaust chamber to the midsection case and the exhaust outlet to the hub. Had it ever so slightly on my '97 and have a buddy now with a '95 that is really bad- I'm gonna do his in the next few weeks. Seems to be common on the 50s.
It doesn't cause a problem- just a mess.
Yes, you have to remove the powerhead to do the job. Should take me about 2 hours to do it.