Motorcycle Repair: 1997 Suzuki intruder GLPV 1400

Question
I changed the spark plugs because the back cylinder wasn't firing and now it's smoking out of the rear exhaust

Answer
Hello Jeff,

Obviously, it's the other way around. What I mean is, whatever makes the bike smoke, fouled the plug up to the point of misfiring.
Probably, the rear carburetor choke is stuck open. Check the starter (choke) cable(s) for rust and sticking. It's a common issue on all Intruders.

Let me know what you found.

Best Regards,
Lazaros.