TOPIC:

I've been doing a lot of restoration work to my KZ440LTD the past month after a year of ownership and learning to ride on it. So far I've had the tank resprayed, new handlebars (Euro style), LED Conversions, tires, chain and sprockets. When I was having the tank resprayed, I put some startron in the tank before I drained it and brought it in but forgot to let it run through the carbs because I'm an idiot. All in all untreated gasoline was in my carburetor for about 3 weeks. Today I finally got the tank back and everything together but when I tried to fire it up I noticed immediately it was having trouble idling, it seemed rough and sort of uneven(?) and would die whenever I pulled the throttle back. Is it safe to assume this is carb related and if so what's my best course of action? I do a lot of work myself but carbs have a bunch of tiny parts and I don't have an organized workspace to take it apart really. Thank you for all your help.

Three weeks shouldn't gum up the jets, maybe some junk in the tank or some other fueling issue is messing with fuel delivery.  Try running with the fuel door open and set the petcock to Prime (the 440 has that, if I remember right, it's been a while since I had one). Run it for a bit, let the additive get into the carbs, let it sit for a while then try again.  Don't pull the carbs if you don't have to. They are a PITA, especially with old, hardened manifolds and boots.  Does the bike run better on choke?