[johnnyrod]

Regulator/rectifiers are funny things, and I've seen bikes before where they'll just about run but not with extras like lights. Sounds like the alternator is fine though - the output is right and if there was any continuity to earth it'd fry itself anyway. Check the continuity from the frame etc. to the battery - though, don't make any assumptions. Re. the fuel, a favourite of older bikes is to rust through the tank at the left side near the fuel tap - the lowest point, so any free water ends up there - so if you're struggling to pinpoint it then check that out.