Virago problem's ( just for a change)

Hi all first post here and I was wondering if anybody could help me and my grandad out as we tearing our hair out over this bike. It's an 88 virago with an intermittent ignition and running issues. Some times it fails to start and sometimes the rear cylinder stops functioning correctly during running. We've just got it out again for another repair attempt and after changing the battery it worked perfectly. Anyone have any ideas because I'm fairly sure the problem hasn't just vanished and can't really risk taking it on a trip t check properly as it might break down. If anyone has had similar problems any advice would be really helpful. Thanks Maxwell 1st