The intake bell of my carburetor has a 1-5/8" long crack in it. Crack was discovered while chasing a weird intermittent running issue, which had to be either the ignition or the carbs. A routine check of the ignition came up empty, so I removed the carbs and found this.
The crack does not seem to extend to the outside of the carb body.
I went to a great deal of trouble trying to determine if the crack extended to the air jet passage (red arrow) and/or the float bowl vent (blue arrow). I used suction, carb cleaner spray, and flooding the passages with paint thinner. All tests came back negative, i.e. no smoking gun was found. However, that doesn't clear the crack as the source of my problems.
It's still possible that my intermittent problem is in the ignition, but I'm leaning toward this crack as the cause.
This is a carb that I've probably been using for a couple of years. Bike ran like a top, but recently it started to become hard to start. More importantly, sometimes it would start and run fine, some times it would start but idle poorly and run at slow speeds poorly. I could shut it down, re-start it and it would be good. Shut it down again, re-start it, and it would be bad. About a 50-50 crap shoot.