GL1100 Damaged carburetor

I have this Cen Tech automotive multimeter I bought at Harbor Freight, and I decided to measure the exhaust header temperatures while my 81 Interstate was idling (or trying to idle) last night. I got 240 degrees on cylinders 1 & 2, but only 140 degrees on cylinders 3 & 4. I put a strobe light on all four spark wires sequentially, and all four flashed the same, so I know I have plenty of spark. My carbs must have clogged idle jets, again.
Today I took off the carbs (much faster than last time). I found some rusty material in float bowls. This time I took off the fuel filter and noticed it was full of dark material. I am going to drain and clean the gas tank tomorrow (I'm on vacation this week).
I noticed the idle jet tower had a corner chipped off it and wondered whether that made a difference in the carb's ability to suck gas out of the float bowl. By idle jet tower, I am referring to the appearance of the three cast tubes that project into the float bowl from above. When you turn the carburetor upside down, they look like towers on a castle. The main jet is the tallest with the brass fixtures on top. The very next one is the idle jet tower with the idle jet recessed within. The third tower goes nowhere.
I don't know whether the tip of the idle jet tower must be immersed in gasoline in order to draw the gas through the jet and into the carb. Is it possible that having a chip off the corner (about 1/4 inch diagonal nicked off) is like having a hole in a straw, thus no suction? Someone must have dropped this carb while working on it, and that's when the chip occurred? Any advice?

Pics?

I doubt the fuel level would ever get low enough for the chip to cause any problems. If the floats are set properly. More likely the trash you found caused some flooding.

1/4" chipped off sounds like a lot.
A pic would help but I do think most if not all those pickup tubes are immersed in gas because the gas level in the bowls is just below the float bowl gasket.

Sorry, I failed to photograph the chipped pickup tube; that would have been more informative. I had a good look into the fuel tank while draining it today. It looks like someone threw a couple handfuls of sand in there. It's all rusty flakes. the fuel gauge sender is also coated with fine rust.
Tomorrow I'm going to pull the tank out,fill it up with bbs and shake it all around. I'm open to any suggestions you may have. :read:

good choice arnold thats probably the your biggest problem your carbs have .....nothing worst than clean carbs inline with a rusty tank to skrew up a carb job :rant: :rant: :rant: :mrgreen:

Once you get most of the rust out I'd suggest electrolysis to finish the job. Then keep the tank full of fuel to prevent condensation.

Here's a photo of the tank interior after I swished 300 bbs through it, first with gas remaining in the tank, then with lemon juice.

i think you did good arnold ....it looks like a huge leap forward on the old wing .... :good: k: good work :builder: :builder: :mrgreen:

you could always line the tank. Kream is the name of one of the liners. I here they work well but have never tried them. Just a thought.