I sorted out an old Norton Commando's carbs (Amal) 5 years and 6,000 miles ago; still fine. I'm at 2 years and 4,000 miles on my CB750K6 (Keihin) since overhaul and a balance with vacuum guages; still good. I also have twin SU carbs on an old car, which can stand for a couple of years, then fire up.
Make sure you have ethanol proof fuel line. I try to avoid E10, but not always possible. If I've not ridden for a couple of weeks, I turn on the fuel to refill the bowls and avoid letting them dry out. I've read and YouTubed fuel stabilisers. Some evangelise about them, some call them snake oil. I haven't found a need for them so far.
I check my points every service (1500 miles) and so far they have needed adjustment once. Ditto the timing. I don't know if that was wear, or being slightly out when i first set it, probably the latter. Both were a little out when I bought the bike. The difference was noticeable. Difficult starting and sooty plugs on 2 and 3 were caused by 2 and 3 being retarded. I am told the advancer mechanism behind the points plate can give an uneven idle. The spring can stretch, causing variation at tickover, also the shaft can bend from over enthusiastic use of the nut on the end of the shaft when manually turning the engine over. Don't know if that's correct? I set my idle at about 1300 rpm hot, to avoid the cam chain, primary chain and clutch rattle that seems to come with a lower idle.
