In the last couple of weeks I've had 2 bikes in here with idling issues on one cylinder. Both bikes are older and using VHB carburetors. The first was an Ambassador, it ran great but, was loading up and fouling the left plug. The owner had tried what he could and then brought it to me. I've seen this problem before and other than having the jets swapped, it's usually the choke plunger. This carb had a piece of the old choke plunger stuck in the bore. Someone along the way could not get it out so, they drilled it out until a new one would fit but, didn't get the whole thing out so it would not seal.
I fished this out but there is still some in there.
The next bike had the opposite problem. It was running too lean on the right cylinder. I could spray a little carb cleaner down the throat and the idle picked right up. My young apprentice had rebuilt the carbs, (it's his newly acquired 850T). He's done a few sets and has the basics down. We pulled the carb and popped on another we had just rebuilt and the bike ran fine. On close inspection this is what I found...
Here's a good carb...
The plugs from the drilling of the idle passages are missing, where they went and why I have no clue. I'm going to try to find some small bearings and peen them in the holes.
Just thought I'd put this out there.