I’m new to this forum and I just bought a vulcan 800. My brother had it for years and couldn’t solve this issue so he sold it to me for almost nothing. It runs like brand new about half the time. Sometimes it has a sputter and it’ll backfire and cough out of the carb. I found a bit of oil in the air breather but not a lot. I’m baffled. I was thinking maybe it’s a fuel air problem but after realizing how it’s only about half the time I’m not sure. Maybe I need new coils? Any thoughts would be greatly appreciated.