76 Honda GL1000, Stumble from Idle 

I'm no expert but this could be a number of things. Condenser earth, worn dash pot springs (original?), throttle cables, fuelling, timing, etc. Plenty of chat on Facebook groups for this bike and Randakks. Good luck with it!

I have had the same situation with my 75 GL1000. My situation is that I don't ride the bike enough. It sits for a month or more without being started. I use Seafoam and Stabil in the fuel and I actually have a gallon of gas mixed so I add it so the tank in the bike always has this mixture in the fuel system. Sometimes I still have a stumble. So what I did, is check the timing, then check the carb synchronization, then check the idle air screws for best idle. I found I have one idle air screw that gets clogged up more than the others. When I start the bike, that cylinder exhaust pipe won't get hot when it has been sitting for a while. So I have to take the screw and turn it out one half a turn, and then back in one half a turn. That loosens the crud in there and when I start the bike, it starts fine. I am hoping by running the Seafoam and the Stabil in the tank it will keep the carbs clean. I also have to take the bike out and ride it at least 30 - 40 miles in various speeds and acceleration to make sure the carbs get used to their fullest extent while riding to keep them cleaned out. Hopefully your carbs are not bad enough where they need more serious attention or even rebuilding. Good Luck and ride safe.