Have purchased a 1984 Virago 750, it has not been run for 5 years, had to strip the carbs down, needed new float needle ass, plus plenty of cleaning, have changed the oil and filter, and fitted a new battery, can get it fired up by covering the carb mouth with a piece of card with hole in, but soon a I take it away the bike cuts out, my friend says it should run without the filter connected, so the carbs can be balanced, is this correct??? hope someone can help, thanks Mac