1996 Vulcan Classic 1500
I have a 1996 Vulcan Classic 1500, actually the same colors as yours. I bought it from the original owner, who, I later found out, had let the bike set for several years without riding it.
Long story short...I ended up replacing the heat sensor in the radiator, the radiator, and horns within days of buying the bike. I than found out that the clutch was on it's way out and had to replace it also, something I questioned the owner about, but he assured me it was just because it was a hydraulic clutch.
I have always experienced the popping, it's very annoying, and at times it sounds like a gun firing. I marbled the hoses on the intake air reed boxes and it stopped it completely, what a relief. Make sure you use real glass marbles and not plastic ones that may melt from the heat of the engine.
I changed the stock filter to a K&N and it seems like that has allowed more air flow as the bike doesn't warm up as quickly and wants to stall when starting off. Everything I read sounded like the bike is running too lean and I needed to re-jet the carb. The original owner had replaced the stock exhaust with DG Hard Krome 3" Slash Cut pipes....which were blue. I figured this was from not changing the jets.
There is a lot of conflicting information out there about whether or not you need to change the jets when you change to after market pipes, but it seems to make sense that you are changing the back pressure on the engine allowing less back pressure which would increase the air flow.
I am about to yank the carb and attempt to change the jets, I bought them on eBay from a guy in California who asked me about all of the after market changes I have made as well as where I live as the altitude directly affect the size of the jets you should have.
But now I'm thinking I will attempt to adjust the air/gas mixture first, I'm thinking this is the adjustment that has the factory installed plug covering it that needs to be drilled out to gain access to it. If I go to all of the trouble of removing the carb I might as well as change out the main jet.
I've put about 3,000 miles on the bike since I bought it last August, pretty good considering all of the down time for repairs. I really like the bike and it gets a lot of comments, even from the Harley owners.
Let me know how things turn out for you and I'll let you know how things worked out with my bike.
I added a picture of my bike.